Atomic Structure and the Periodic Table C1 Flashcards
(179 cards)
1
Q
What are all substances made of?
A
All substances are made of atoms.
2
Q
What do atoms contain?
A
Atoms contain protons, neutrons, and electrons.
3
Q
What is the radius of an atom?
A
Atoms have a radius of about 0.1 nanometres.
4
Q
What is located in the middle of the atom?
A
The nucleus is in the middle of the atom.
5
Q
What particles are found in the nucleus?
A
The nucleus contains protons and neutrons.
6
Q
What is the charge of the nucleus?
A
The nucleus has a positive charge because of the protons.
7
Q
What is the charge of electrons?
A
Electrons are negatively charged.
8
Q
How does the number of protons relate to the number of electrons in an atom?
A
The number of protons equals the number of electrons.
9
Q
What determines the size of the atom?
A
The volume of the electron orbits determines the size of the atom.
10
Q
How do you find the number of neutrons?
A
To get the number of neutrons, subtract the atomic number from the mass number.
11
Q
What is the atomic number?
A
The atomic number tells you how many protons there are.
12
Q
What is an ion?
A
An ion is an atom or group of atoms that has lost or gained electrons.
13
Q
What is the nuclear symbol of an atom?
A
The nuclear symbol tells you its atomic (proton) number and mass number.
14
Q
What is the atomic number and mass number of gallium?
A
An atom of gallium has an atomic number of 31 and a mass number of 70.
15
Q
What is the nuclear symbol for sodium?
A
The nuclear symbol for sodium is Na with atomic number 11 and mass number 23.
16
Q
What are compounds?
A
Compounds are substances formed from two or more elements, with atoms in fixed proportions held together by chemical bonds.
17
Q
How do atoms join to form compounds?
A
Atoms combine with other atoms when elements react to form compounds.
18
Q
What is involved in making chemical bonds?
A
Making bonds involves atoms giving away, taking, or sharing electrons; the nuclei of the atoms aren’t affected.
19
Q
What is ionic bonding?
A
Ionic bonding occurs when a compound formed from a metal and a non-metal consists of ions, where metal atoms lose electrons to form positive ions and non-metal atoms gain electrons to form negative ions.
20
Q
What are examples of compounds bonded ionically?
A
Examples include sodium chloride, magnesium oxide, and calcium oxide.
21
Q
What is covalent bonding?
A
Covalent bonding occurs in compounds formed from non-metals, where each atom shares an electron with another atom.
22
Q
What are examples of compounds bonded covalently?
A
Examples include hydrogen chloride gas, carbon monoxide, and water.
23
Q
How do the properties of a compound compare to the original elements?
A
The properties of a compound are usually totally different from the properties of the original elements.
24
Q
What is the formula for carbon dioxide?
A
The formula for carbon dioxide is CO2.
25
What is the formula for ammonia?
The formula for ammonia is NH3.
26
What is the formula for water?
The formula for water is H2O.
27
What does a formula represent in a compound?
Formulas are made up of elemental symbols in the same proportions that the elements can be found in the compound.
28
What is the formula for sulfuric acid?
The formula for sulfuric acid is H2SO4.
29
What is the formula for hydrochloric acid?
The formula for hydrochloric acid is HCl.
30
What is the formula for sodium chloride?
The formula for sodium chloride is NaCl.
31
What is the formula for calcium chloride?
The formula for calcium chloride is CaCl2.
32
What is the formula for sodium carbonate?
The formula for sodium carbonate is Na2CO3.
33
What is the formula for iron sulfide?
The formula for iron sulfide is FeS.
34
What elements are in the compound Al2(SO4)3?
The elements are aluminum (Al) and sulfur (S), along with oxygen (O).
35
What happens during a chemical reaction?
During a chemical reaction, at least one new substance is made, and you can usually measure a change in energy.
36
What are chemical equations fundamental to?
Chemical equations are fundamental to chemistry.
37
What do chemical equations show?
Chemical changes are shown using chemical equations.
38
What are the reactants in a chemical equation?
The molecules on the left-hand side of the equation are called the reactants.
39
What is an example of a word equation?
Methane burns in oxygen giving carbon dioxide and water.
## Footnote
Example: methane + oxygen → carbon dioxide + water
40
What do symbol equations show?
Symbol equations show the symbols or formulas of the reactants and products.
41
What must be true for a balanced chemical equation?
There must always be the same number of atoms on both sides.
42
How do you balance a chemical equation?
You balance the equation by putting numbers in front of the formulas where needed.
43
What is an example of a symbol equation?
H₂SO₄ + NaOH → Na₂SO₄ + H₂O
## Footnote
Example: 2Mg + O₂ → 2MgO
44
What should you do if you find an unbalanced element?
Pencil in a number to try and sort it out.
45
What happens if balancing creates another imbalance?
If it creates another imbalance, pencil in another number and see where that gets you.
46
What is the right-hand side of a chemical equation called?
The molecules on the right-hand side are called the products.
47
What is the goal of revision in balancing equations?
Revision is all about getting the balance right.
48
What is the key to mastering balancing equations?
Balancing equations is all about practice.
49
What are mixtures in chemistry?
Mixtures in chemistry consist of lots of separate things all mixed together.
50
How can the parts of a mixture be separated?
The parts of a mixture can be separated using physical methods such as filtration, crystallization, simple distillation, fractional distillation, and chromatography.
51
What is an example of a mixture?
Air is a mixture of gases, mainly nitrogen, oxygen, carbon dioxide, and argon.
52
What is crude oil a mixture of?
Crude oil is a mixture of different length hydrocarbon molecules.
53
How do the properties of a mixture relate to its components?
The properties of a mixture are just a combination of the properties of the separate parts; the chemical properties of a substance aren't affected by being part of a mixture.
## Footnote
For example, a mixture of iron powder and sulfur powder will show the properties of both iron and sulfur.
54
What is paper chromatography?
Paper chromatography is a method used to separate substances in a mixture, such as different dyes in an ink.
55
What should you use to draw the line on filter paper for chromatography?
You should use a pencil to draw the line on filter paper because pencil marks are insoluble and won't dissolve in the solvent.
56
What happens when the solvent moves up the paper in chromatography?
The solvent seeps up the paper, carrying the ink with it, and each different dye will move up the paper at a different rate, forming spots.
57
What is a chromatogram?
The end result of chromatography is a pattern of spots called a chromatogram.
58
What is the solvent front in chromatography?
The solvent front is the point the solvent has reached as it moves up the paper.
59
Why shouldn't you use a pen to draw a line on the filter paper for paper chromatography?
You shouldn't use a pen because pen marks are soluble and can dissolve in the solvent, affecting the results.
60
What are some real-life applications of chromatography?
Chromatography is used to test athletes' urine samples for performance-enhancing drugs and to test unknown substances at crime scenes.
61
What is filtration used for?
Filtration is used to separate insoluble solids from liquids.
62
What are two methods to separate soluble solids from solutions?
The two methods are evaporation and crystallisation.
63
What happens during evaporation?
The solvent evaporates, concentrating the solution until crystals form.
64
What is the first step in crystallisation?
Pour the solution into an evaporating dish and gently heat it.
65
What should you do when you see crystals start to form during crystallisation?
Remove the dish from heat and leave the solution to cool.
66
How can you separate rock salt?
Filter the mixture to separate sand (insoluble) from salt (soluble).
67
What is a vital difference between salt and sand?
Salt dissolves in water, while sand does not.
68
What can be used instead of a Bunsen burner for heating?
You could use a water bath or an electric heater.
69
How can you produce pure crystals of copper sulfate?
Use crystallisation to separate it from an aqueous solution.
70
What is distillation used for?
Distillation is used to separate mixtures which contain liquids.
71
What are the two types of distillation?
The two types of distillation are simple distillation and fractional distillation.
72
What is simple distillation used for?
Simple distillation is used for separating out a liquid from a solution.
73
What happens during simple distillation?
The solution is heated, and the part with the lowest boiling point evaporates first.
74
What occurs after the vapor is produced in simple distillation?
The vapor is cooled, condenses, and is collected.
75
What is left behind after simple distillation?
The rest of the solution is left behind in the flask.
76
Can you give an example of simple distillation?
You can use simple distillation to get pure water from seawater. The water evaporates and is condensed and collected, leaving just the salt in the flask.
77
What is a limitation of simple distillation?
Simple distillation can only separate substances with very different boiling points.
78
What method is used to separate liquids with similar boiling points?
Fractional distillation is used to separate a mixture of liquids with similar boiling points.
79
What is the setup for fractional distillation?
You put your mixture in a flask, attach a fractionating column on top, and heat it.
80
How do different liquids behave during fractional distillation?
Different liquids will evaporate at different temperatures based on their boiling points.
81
What happens when the temperature matches the boiling point of a liquid in fractional distillation?
When the temperature matches the boiling point, the liquid evaporates and reaches the top of the column.
82
What occurs to liquids with higher boiling points during fractional distillation?
Liquids with higher boiling points might start to evaporate, but they will condense and run back down towards the flask.
83
What do you do after collecting the first liquid in fractional distillation?
You raise the temperature until the next liquid reaches the top.
84
What is a practical application of fractional distillation?
Fractional distillation can be used to separate a mixture of compounds like propan-1-ol, methanol, and ethanol.
85
What did John Dalton describe atoms as at the start of the 19th century?
John Dalton described atoms as solid spheres, with different spheres making up different elements.
86
What did J J Thomson conclude about atoms in 1897?
J J Thomson concluded that atoms weren't solid spheres and must contain smaller, negatively charged particles called electrons.
87
What is the 'plum pudding model'?
The 'plum pudding model' showed the atom as a ball of positive charge with electrons stuck in it.
88
What experiment did Ernest Rutherford conduct in 1909?
Ernest Rutherford and his student Ernest Marsden conducted the alpha particle scattering experiments by firing positively charged alpha particles at a thin sheet of gold.
89
What were the expectations of the plum pudding model during Rutherford's experiment?
They expected the alpha particles to pass straight through the gold sheet or be slightly deflected.
90
What did Rutherford's experiment reveal about the atom?
Some alpha particles were deflected more than expected, indicating that the plum pudding model was incorrect.
91
What is the nuclear model of the atom proposed by Rutherford?
The nuclear model describes a tiny, positively charged nucleus at the center, surrounded by a 'cloud' of negative electrons, with most of the atom being empty space.
92
What did Niels Bohr propose about electron orbits?
Niels Bohr proposed that electrons orbit the nucleus in fixed shells and aren't found in between.
93
What did further experiments show about the nucleus?
Further experiments showed that the nucleus can be divided into smaller particles called protons.
94
Who provided evidence for neutrons in the nucleus?
James Chadwick provided evidence for neutral particles in the nucleus, which are now called neutrons.
95
What is the modern accepted model of the atom?
The modern accepted model of the atom is known as the nuclear model.
96
What causes the whole of chemistry?
The fact that electrons occupy 'shells' around the nucleus.
97
What are the Electron Shell Rules?
1) Electrons always occupy shells (sometimes called energy levels).
2) The lowest energy levels are always filled first.
3) Only a certain number of electrons are allowed in each shell: 1st shell: 2, 2nd shell: 8, 3rd shell: 8.
4) Atoms are much happier when they have full electron shells like the noble gases in Group 0.
5) In most atoms, the outer shell is not full, making the atom want to react to fill it.
98
How can you work out the electronic structures for the first 20 elements?
You can easily work out the electronic structures for the first 20 elements of the periodic table.
99
What is the electronic structure of nitrogen?
The electronic structure for nitrogen must be 2, 5.
## Footnote
Nitrogen's atomic number is 7, meaning it has 7 electrons.
100
What is the electronic structure of magnesium?
The electronic structure for magnesium must be 2, 8, 2.
## Footnote
Magnesium's atomic number is 12.
101
What is the electronic structure of argon (atomic number = 18)?
The electronic structure of argon is 2, 8, 8.
102
What is the electronic structure of aluminium (atomic number = 13)?
The electronic structure of aluminium is 2, 8, 3.
103
What is the electronic structure of calcium (atomic number = 20)?
The electronic structure of calcium is 2, 8, 8, 2.
104
How do electronic structures appear?
Electronic structures may be shown as diagrams or as numbers like 2, 8, 1.
105
What is the electronic structure of sodium?
The electronic structure of sodium is 2, 8, 1.
106
What is the electronic structure of boron?
The electronic structure of boron is 2, 3.
107
What should you do to master electronic structures?
Practice the rules to work out electronic structures.
108
How were elements classified in the early 1800s?
Elements were mainly arranged by atomic weight, but Mendeleev switched the order if properties indicated a change.
## Footnote
An example is iodine, which has a smaller atomic weight than tellurium but is placed after it due to similar properties.
109
What significant contribution did Dmitri Mendeleev make to the periodic table?
Mendeleev arranged 50 known elements into his Table of Elements, leaving gaps for undiscovered elements and predicting their properties.
## Footnote
He made accurate predictions about an element he called ekasilicon, known today as germanium.
110
What was the main limitation of early periodic tables?
Early periodic tables were incomplete and sometimes placed elements in the wrong groups due to reliance on atomic weight without considering properties.
111
What confirmed Mendeleev's approach to arranging elements?
The discovery of isotopes in the early 20th century confirmed that elements should not only be arranged by atomic weight but also by their properties.
112
What does atomic weight refer to in modern terms?
Atomic weight is equivalent to what we now call 'relative atomic mass'.
113
What pattern did early chemists notice when arranging elements by atomic weight?
A periodic pattern in the properties of the elements was noticed, leading to the name 'periodic table'.
114
What is the periodic table?
The periodic table is a chart that organizes the elements based on increasing atomic (proton) number.
115
How many elements are in the periodic table?
There are approximately 100 elements that all materials are made of.
116
What does the periodic table help to identify?
It helps to see patterns in the properties of elements.
117
What are the two main categories of elements in the periodic table?
Metals and non-metals.
118
Where are metals located in the periodic table?
Metals are found to the left.
119
Where are non-metals located in the periodic table?
Non-metals are found to the right.
120
What are vertical columns in the periodic table called?
These vertical columns are called groups.
121
What does the group number indicate?
The group number tells you how many electrons there are in the outer shell.
122
What is the exception to the group number rule regarding outer shell electrons?
Group 0 elements, like Helium, have two electrons in their outer shell.
123
How do reactivity trends work in Group 1 and Group 7?
In Group 1, reactivity increases down the group; in Group 7, reactivity decreases down the group.
124
What are the horizontal rows in the periodic table called?
The rows are called periods.
125
What does each new period represent?
Each new period represents another full shell of electrons.
126
How can you predict the properties of elements in the same group?
If you know the properties of one element, you can predict properties of other elements in that group.
127
What is the significance of the periodic table in chemistry?
It allows us to see trends in reactivity and properties, enabling predictions about how reactions will occur.
128
What are metals?
Metals are elements which can form positive ions when they react.
## Footnote
They're towards the bottom and to the left of the periodic table.
129
Where are non-metals located in the periodic table?
Non-metals are at the far right and top of the periodic table.
## Footnote
Non-metals don't generally form positive ions when they react.
130
How do atoms generally react?
Atoms generally react to form a full outer shell by losing, gaining, or sharing electrons.
131
Why is it easier for metals to form positive ions?
Metals towards the bottom of the periodic table have outer electrons that are a long way from the nucleus, requiring less energy to remove them.
132
What are the physical properties of metals?
Metals are strong, malleable, great conductors of heat and electricity, and have high boiling and melting points.
133
How do non-metals differ from metals in terms of physical properties?
Non-metals tend to be dull looking, more brittle, not always solids at room temperature, do not generally conduct electricity, and often have lower density.
134
What type of ions do metals generally form?
Metals generally form positive ions due to their position in the periodic table.
135
What type of ions does iodine generally form?
Iodine generally reacts by forming negative ions.
## Footnote
Iodine is a non-metal.
136
What is the relationship between metals and non-metals?
Metals and non-metals have different properties and behaviors in reactions.
137
What are the alkali metals in Group I?
The alkali metals are lithium, sodium, potassium, rubidium, caesium, and francium.
138
What makes alkali metals highly reactive?
They all have one electron in their outer shell, which makes them very reactive and gives them similar properties.
139
What are the physical properties of alkali metals?
The alkali metals are all soft and have low density.
140
What trends occur in alkali metals as you go down Group 1?
Increasing reactivity, lower melting and boiling points, and higher relative atomic mass.
141
How do alkali metals form ions?
The Group I elements readily form 1+ ions by losing their one outer electron to achieve a full outer shell.
142
What happens when Group 1 metals react with water?
They react very vigorously, producing hydrogen gas and forming alkaline solutions.
143
Write the word equation for the reaction between sodium and water.
sodium + water → sodium hydroxide + hydrogen
144
What occurs when Group 1 metals react with chlorine?
They react vigorously when heated, forming white salts called metal chlorides.
145
What do Group 1 metals form when they react with oxygen?
They form metal oxides, with different types of oxide depending on the Group I metal.
146
What is the trend in reactivity of alkali metals?
Reactivity increases as you go down the group, making reactions more vigorous.
147
What happens to the hydrogen produced in reactions with alkali metals?
The amount of energy given out increases down the group, and for potassium and below, there's enough energy to ignite hydrogen.
148
Why do Group 1 metals tarnish in the air?
They react with oxygen in the air to form a dull metal oxide layer.
149
What are the Group 7 elements known as?
The halogens.
150
What is the trend in reactivity of halogens as you go down Group 7?
They become less reactive.
151
What happens to the melting and boiling points of halogens as you go down Group 7?
They have higher melting and boiling points.
152
What is the state of Fluorine at room temperature?
A very reactive, poisonous yellow gas.
153
What is the state of Chlorine at room temperature?
A fairly reactive, poisonous dense green gas.
154
What is the state of Bromine at room temperature?
A dense, poisonous, red-brown volatile liquid.
155
What is the state of Iodine at room temperature?
A dark grey crystalline solid or a purple vapour.
156
How do halogens exist?
As molecules which are pairs of atoms.
157
What type of ions do halogens form when they bond with metals?
1- ions called halides (F-, Cl-, Br-, I-).
158
What type of bonding occurs between halogen atoms and other non-metals?
Covalent bonding.
159
What is formed when halogens react with non-metals?
Compounds that have simple molecular structures.
160
What is a displacement reaction in the context of halogens?
A more reactive halogen can displace a less reactive one from its salt.
161
Give an example of a displacement reaction involving halogens.
Chlorine can displace bromine and iodine from their salts.
162
Why do Group 7 elements get less reactive as you go down the group?
It becomes harder to gain an extra electron due to the outer shell being further from the nucleus.
163
What can you predict about the boiling points of halogens?
Iodine will have a higher boiling point than chlorine as it's further down the group.
164
What are Group 0 elements known as?
Group 0 elements are known as noble gases.
165
What is the reactivity of noble gases?
Noble gases are inert and do not react with much at all.
166
What are the characteristics of Group 0 elements?
Group 0 elements are all inert, colourless gases.
167
Which elements are included in Group 0?
Group 0 elements include helium, neon, argon, krypton, xenon, and radon.
168
How many electrons do noble gases have in their outer energy level?
All noble gases have eight electrons in their outer energy level, except helium, which has two.
169
What state do noble gases exist in?
Noble gases exist as monatomic gases, meaning they are single atoms not bonded to each other.
170
What is the color of noble gases at room temperature?
All elements in Group 0 are colourless gases at room temperature.
171
Are noble gases flammable?
Noble gases are non-flammable.
172
What trend occurs in the boiling points of noble gases?
The boiling points of noble gases increase as you move down the group along with increasing relative atomic mass.
173
What is the boiling point of argon?
The boiling point of argon is -185.8 °C.
174
What is the boiling point of krypton?
The boiling point of krypton is -157.4 °C.
175
What is the boiling point of xenon?
The boiling point of xenon is approximately -108 °C.
176
How can you predict the boiling point of xenon?
Xenon's boiling point can be predicted to be halfway between the boiling points of radon (-62 °C) and krypton (-153 °C).
177
What is the boiling point of radon?
The boiling point of radon is -62 °C.
178
What is the boiling point of neon?
The boiling point of neon is -246 °C.
179
Why are noble gases unreactive?
Noble gases are unreactive because they have a full outer shell of electrons.
