Atomic Structure and the Periodic table Flashcards
(186 cards)
1
Q
What are all substances made of
A
Atoms
it is the smallest part of an element that can exist
2
Q
What do atoms have a radius of
A
0.1 nanometres ( 1x 10-10 m)
3
Q
What contains almost the whole mass of the atom..
A
concentrated in the nucleus
4
Q
What does the nucleus contain
A
protons and neutrons
5
Q
What is the radius of the nucleus
A
1x 10 ^-14
around 1/10,000 of the atom radius
6
Q
What is the relative mass and charge of the PROTON
A
relative mass: 1
charge: +1
7
Q
What is the relative mass and charge of the NEUTRON
A
relative mass: 1
charge: 0
8
Q
What is the relative mass and charge of the ELECTRON
A
relative mass: virtually no mass
charge: -1
9
Q
Where are electrons in an atom
A
-move around the nucleus in electron shells
-volume of their orbits determines the size of the atom
10
Q
Why are atoms neutral and have no charge overall?
A
-this is bcs they have the same number of protons and electrons
-so the charge is the same of the protons and electrons and cancel eachother out
11
Q
Why does an ion have an overall charge
A
-the number of protons does not equal the number of electrons
12
Q
How many more electrons than protons are there in an ion with a -2 charge
A
2 more electrons
13
Q
What does the nucleur symbol of an atom tell u
A
its atomic proton number and mass number
14
Q
What does the atomic number (at bottom) tell u
A
-tells u how many protons there are
15
Q
What does the mass number (at the top) tell u
A
the total number of protons and neutrons in the atom
16
Q
How do u get the number of neutrons
A
-subtract the atomic number from the mass number
17
Q
What is an element
A
is a substance made up of atoms that all have the same number of protons in their nucleus
18
Q
What determines what type of atom something is
A
number of protons in the nucelus decides
19
Q
What is an atom with one proton
A
hydrogen
20
Q
What is an atom with two protons
A
helium
21
Q
What is a substance that contains atoms with the name number of protons
A
an element
22
Q
So different elements..
A
have atoms with dif number of protons
23
Q
What are elements represented by
A
one or two letter symbol
24
Q
What are Isotopes
A
-different forms of the same element which have
-the same number of protons but a dif number of neutrons
25
So what do Isotopes have
Same atomic number
dif mass numbers
26
What is a v popular pair of isotopes
carbon-12
carbon-13
27
So compare how many neutrons in Carbon-12 and carbon-13
carbon-12: 6 neutrons
carbon-13: 7 neutrons
28
As many elements can exist as a number of dif isotopes so what is taken
-relative atomic mass (Ar) instead of mass number
-when refering to the element as a whole
29
What is relative atomic mass
an average mass taking into account the differnt masses and abundances of all the isotopes that make up the element
30
How to find Relative Atomic mass (Ar)
=sum of(isotope abundanceX isotope mass number)
divided by
sum of abundances of all the isotopes
31
What is isotope abundance
a percentage that will be given in the exam
32
When elements react what happens
-Atoms combine with other atoms to form compounds
33
What are compounds
are substances formed from two or more elements ,
-the atoms of each are in fixed proportions throughout the compound
-held together by chemical bonds
34
How do atoms make bonds
making bonds involves atoms giving away,taking or sharing electrons
35
When atoms make bonds what isn't affected
-nuclei of the atoms aren't affected at all when a bond is made
36
How to seperate a compound
-a chemical reaction
usually difficult to seperate the og elements
37
What does a compound formed from a metal and non metal consist of
ions
38
What is ionic bonding
opposite charges of the ions in positive and negative means they are strongly attracted to eachother
39
How are metal atoms positive (ionic bonding)
they lose electrons to form positive ions
40
How are nonmetal atoms positive (ionic bonding)
gain electrons to form negative ions
41
Examples of compounds which are ionically bonded
-sodium chloride
-magnesium oxide
-calcium oxide
42
What does a compound formed by non metals consist of
consists of molecules
43
What is covalent bonding
each atom shares an electron with another atom
44
What are examples of compounds that are bonded covalently
-hydrogen chloride gas
-carbon monoxide
-water
45
Compare properties of a compound with the original elements
compound usually have totally different properties of the original elements
46
Compare the mixture of iron and sulfur and the compound formed after heating of iron sulfide
iron(magnetic metal) and sulfur (nice yellow powder)
-compound is a dull grey solid lump and doesn't behave anything like iron or sulfer
47
What are compounds represented by
by formulas
48
What are the formulas made up of
elemental symbols in the same proportions that the elements can be found in the compound
49
What is carbon dioxide formed from
formed from a chemical reaction between carbon and oxygen
-contains 1 carbon atom and 2 oxygen atoms
CO2
50
What is the formula of sulfuric acid
H2 SO4
-each molecule contains 2 hydrogen atoms ,1 sulfur atom, 4 oxygen atoms
51
Formula for calcium hydroxide
Ca(OH)2
1 calcium atom, 2 oxygen atoms, 2 hydrogen atoms
52
What do the brackets mean in calcium hydroxide Ca(OH)2
little number outside the bracket applies to everything inside the brackets
53
Formula for Ammonia
NH3
54
Formula for water
H2 O
55
Formula for sodium chloride
NaCl
56
Formula for Carbon monoxide
CO
57
Formula for hydrochloric acid
HCl
58
Formula for Calcium chloride
CaCl2
59
Formula for sodium carbonate
Na2 CO3
60
What are the 2 different ways to show chemical equations
-Word equation
-Symbol equations
61
For symbol equations how must it be balanced
must be the same number of atoms on both side
-have to add numbers infront
62
Difference between a compound or mixture
no chemical bond between different parts of a mixture
63
What can parts of a mixture be
can be either elements or compounds
64
How can mixtures be seperated
-seperated by physical methods
eg. Filtration, Crystallisation, simple distillation, fractional distillation, chromotography
65
What is Air a mixture of
a mixture of gases ,mainly nitrogen,oxygen, carbon dioxide and argon
66
How easily can gases be seperated
fairly easily
67
What is crude oil a mixture of
a mixture of different length hydrocarbon molecules
68
How are properties of a mixture differ to the properties of seperate parts
chemical properties of a substance aren't affected by it in a mixture
69
Eg of a mixture with same properties
mixture of iron powder and sulfur powder will contain both properties
-grey magnetic bits of iron and bright yellow sulfur bits
70
How to seperate dyes
Chromotography
71
How to seperate insoluble solids from liquids
filtration
72
What else does filtration can be used with
-in purification
eg. solid impurities seperated out
73
How to seperate soluble solids from solutions
-Evaporation
-Crystalisation
74
When do u have to use crystalisation instead of evaporation
-evaporation quick way to seperate soluble salt
-only can use if the salt doesn't decompose when its heated
-otherwise use crystalisaiton
75
What can filtration and crystalisation be used for
to seperate rock salt
76
What is rock salt
a mixture of salt and sand
77
Why should crystalisation be used
if you want to make nice big crystals of ur salt
78
How to seperate mixtures which contain liquids
-simple distillation
-fractical distillation
79
At the start of the 19th centuary what were atoms described as
-John Dalton described atoms as solid spheres and said that dif spheres made up the different elements
80
What idea did JJ Thomson have in 1897
-weren't js solid spheres
-Plum pudding model showed the atom as a ball of positive charge with electrons stuck in it
81
What did Ernest Rutherford do in 1909
-conducted the famous alpha particle scattering experiments
-fired positively charged alpha particles at an extremely thin sheet of gold
82
What was expected in Ernest Rutherford's experiment
-expecting the particles to pass straight through the sheet or be slightly deflected at most
83
Why was this expected in Rutherford's experiement
-as the positive charge of each atom was thought to be very spread out through the pudding of the atom
84
What was the results of Rutherford's experiment
-most particles did go straight through the gold sheet
-some were deflected more than expected
-a small were deflected backwards
85
What did Rutherford come up with
The Nucleur model of the atom
86
What was Rutherford's nucleur model
-tiny positively charged nucleus at the centre, most mass concentrated
-most atom empty space
-surround negative electrons in a 'cloud'
87
Why were the atoms deflected (rutherford)
when they came near the concentrated positive charge of the nucleus
88
Why were the atoms deflected backwards (rutherford)
if they were fired directly at the nucleus
89
Why did the atoms go straight through (rutherford)
passed through empty space
90
What did Neil Bohr discover
if the electrons were in a cloud they wld be attracted to the nucelus and cause atom to collapse
91
What did Neil Bohr propose
that electrons orbit the nucleus in fixed shells
-each shell is fixed distance from the nucleus
92
What did Further experiments from Rutherford show
-that the nucleus can be divided into smaller particles which each have the same charge as a hydrogen nucleus
-these particles were called protons
93
Who proved the existence of neutrons
James Chadwick
20yrs after acceptance of nucleus
94
What did the discovery of neutrons result in
a model of the atom known as the nucleur model
95
where do electrons occupy
shells
often called energy levels
96
Which energy levels are first filled with electrons
the lowest ones (closest to the nucleus)
97
How many electrons are allowed in the 1st shell
2
98
How many electrons are allowed in the 2nd and 3rd shell each
8 electrons each
99
What do atoms want (shells)
want full energy shells
100
What group has already full energy shells
Noble gases in group 0
101
How were elements catagorised in early 1800s
1.Their weight
2.Their physical and chemical properties
102
Why was there no such thing as atomic number in early 1800s
as scientists had no idea of atomic structure or of protons,neutrons or electrons
103
Problems with early periodic tables
-Were not complete
-some elements placed in the wrong groups
-this is bcs they were placed in order or atomic weight and did not take into account their properties
104
What happened in 1869
Dmitri Mendeleev took 50 known elements and arranged them into his Table of elements
105
What order did Dmitri put the elements into
-mainly in order of atomic weight
-but moved them if the properties meant it shld be changed
106
Example of Dmitri switching the order due to properties
-Te and I
-iodine has a smaller atomic weight but is placed after tellurium as it has similar properties to the elements in that group
107
Why did Dmitri leave gaps in his table
-elements with similar properties stayed in the same groups
-some of the gaps indicated the exsistance of undiscovered elements
-He could predict the properties of unknown ones
108
When his predictions were proven right what did this mean
helped confirm his ideas and table
109
give an example of one of his predictions
made good predictions of the chemical and physical properties of an element he called ekasilicon (germanium)
110
What did the discovery of isotopes in the early 20th centuary confirm
That Mendeleev was correct to not place elements in a strict order of atomic weight but also take account of their properties
111
What do isotopes of the same element have or not have
-have different masses
-have the same chemical properties
so occupy same position on the periodic table
112
How many elements are there
100 ish
113
What is the purpose of the periodic table?
The periodic table helps you to see patterns in properties of elements.
114
How many elements are there in the periodic table?
There are approximately 100 elements
-which all materials are made of
115
Where are metals and non-metals located in the periodic table?
Metals are found to the left
non-metals to the right.
116
What do vertical columns in the periodic table represent?
-Vertical columns are called groups, -elements in the same group have similar properties.
117
What does the group number indicate?
The group number tells you how many electrons there are in the outer shell.
118
What is an exception to the group number rule?
Group 0 elements, like Helium, have two electrons in their outer shell.
119
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.
120
What trend is observed in reactivity for Group 1 elements?
In Group 1, the elements react more vigorously as you go down the group.
121
What trend is observed in reactivity for Group 7 elements?
In Group 7, reactivity decreases as you go down the group.
122
What are the rows in the periodic table called?
The rows are called periods, and each new period represents another full shell of electrons.
123
How are the elements ordered in the modern periodic table
Order of increasing atomic number
124
What are metals?
-are elements which can form positive ions when they react
-are located towards the bottom
- to the left of the periodic table.
125
Where are non-metals located on the periodic table?
Non-metals are at the far right and top of the periodic table.
126
Do non-metals generally form positive ions?
No, non-metals don't generally form positive ions when they react.
127
What affects how atoms will react?
Atoms generally react to form a full outer shell by losing, gaining, or sharing electrons.
128
Why is it easier for metals to form positive ions?
-Metals to the left of the periodic table have fewer electrons to remove
-those towards the bottom have outer electrons that are further from the nucleus, resulting in weaker attraction.
129
What is the physical property of metals?
-All metals have metallic bonding so similar properties
-strong
-malleable
-good conductors of heat and electricity
- having high boiling and melting points.
130
What are the physical properties of non-metals?
- no metallic bonding
-tend to be dull looking
-more brittle
-not always solids at room temperature
-do not generally conduct electricity
-often have a lower density.
131
What is the difference in bonding between metals and non-metals?
Metals have metallic bonding, while non-metals do not, leading to different physical properties.
132
What is a consequence of non-metals not having metallic bonding?
Non-metals form a variety of different structures and have a wide range of chemical properties.
133
Picture of where non metals and metals are on periodic table
134
Why is it more difficult for non metals to form positive ions by loosing electrons?
-either to the right where they have a lot of electrons to remove to get a full outer shell
-or towards top where outer electrons close to nucleus so a strong attraction
135
What is more feasible for metals to do
The elements to react to form positive ions with a full outer shell
-so not much energy is needed to remove electrons
136
What is more feasible for non metals to do
For them to either share or gain electrons to get a full outer shell
137
What are Group 1 elements known as?
the alkali metals.
138
What are the alkali metals?
The alkali metals are lithium, sodium, potassium, rubidium, caesium, and francium.
139
What is a characteristic of alkali metals regarding their outer shell?
all have one electron in their outer shell, making them very reactive and gives them similar properties
140
What are the physical properties of alkali metals?
The alkali metals are all soft and have low density.
141
What are the trends for alkali metals as you go down Group 1?
1) Increasing reactivity
2) Lower melting and boiling points. 3) Higher relative atomic mass.
142
How do alkali metals form ionic compounds?
The Group 1 elements readily lose their one outer electron to form I+ ions.
Don’t need much energy
143
What do alkali metals produce when they react with water?
They produce hydrogen gas and form hydroxides that dissolve in water to give alkaline solutions.
144
What happens when Group 1 metals react with water?
They react very vigorously
- more reactive metals(lower down) having more violent reactions.
145
What is the reaction of sodium with water?
sodium + water → sodium hydroxide + hydrogen
146
What do alkali metals produce when they react with chlorine gas
React vigorously
They form white salts called metal chlorides
As u go down group , more vigorous
147
What is the reaction of sodium with chlorine?
2Na + Cl2 → 2NaCl
Sodium+chlorine—>sodium chloride
148
What do Group 1 metals form when they react with oxygen?
They form metal oxides.
149
What happens to alkali metals in air?
They tarnish in the air, forming a dull metal oxide layer.
150
What oxide does lithium form when reacting with oxygen?
Lithium reacts to form lithium oxide (Li2O).
151
What oxides does sodium form when reacting with oxygen?
Sodium reacts to form a mixture of sodium oxide (Na2O) and sodium peroxide (Na2O2).
152
What oxides does potassium form when reacting with oxygen?
Potassium reacts to form a mixture of potassium peroxide (K2O2) and potassium superoxide (KO2).
153
Why does group 1 increase in reactivity as it goes down
-The outer electron is more easily lost as the attraction between the nucleus and electron decreases
- as the electron is further away from the nucleus the further down
154
What do alkali metal ionic compounds with non metals look like
Generally white solids that dissolve in water to form colourless solutions
155
How do Lithium , sodium and potassium react with water
Float and move around the surface , fizzing furiously
-potassium can ignite hydrogen
156
What are the Group 7 elements commonly known as?
The Group 7 elements are known as the halogens.
157
What are the physical states of halogens?
Halogens are all non-metals with coloured vapours.
158
What is the state and color of Fluorine?
Fluorine is a very reactive, poisonous yellow gas.
159
What is the state and color of Chlorine?
Chlorine is a fairly reactive, poisonous dense green gas.
160
What is the state and color of Bromine?
Bromine is a dense, poisonous, red-brown volatile liquid.
161
What is the state and color of Iodine?
Iodine is a dark grey crystalline solid or a purple vapour.
162
How do halogens exist?
They all exist as molecules which are pairs of atoms.
163
What happens to reactivity as you go down Group 7?
Halogens become less reactive as you go down Group 7.
164
What happens to melting and boiling points as you go down Group 7?
Melting and boiling points increase as you go down Group 7.
165
What happens to relative atomic masses as you go down Group 7?
Relative atomic masses increase as you go down Group 7.
166
What is a trend you can predict about iodine compared to chlorine?
Iodine will have a higher boiling point than chlorine.
167
Why do all Group 7 elements react in similar ways?
They all have seven electrons in their outer shell.
168
How do halogens form molecular compounds?
Halogen atoms can share electrons via covalent bonding with other non-metals to get a full outer shell
169
What are examples of compounds that contain covalent bonds with halogens and non metals?
Examples include HCl, PCl5, HF, and CCl4.
170
What type of ions do halogens form when they bond with metals?
Halogens form 1- ions called halides (F-, Cl-, Br-, and I-).
171
What type of structures do compounds formed by halogens and metals have?
The compounds have ionic structures.
172
What can a more reactive halogen do in a displacement reaction?
A more reactive halogen can displace a less reactive one from its salt.
173
Give an example of a displacement reaction involving halogens.
-Chlorine can displace bromine and iodine from their aqueous solutions.
-Bromine will also displace iodine due to reactivity trend
174
Name me the 4 Halogens
-Fluorine
-Chlorine
-Bromine
-Iodine
175
What does ionic bonding look like between halogens and metals
176
What are Group 0 elements commonly known as?
noble gases.
177
What are the characteristics of noble gases?
-so energetically stable
-means they are mostly inert and won’t move react with much at all
178
Which elements are included in Group 0?
Group 0 elements include helium, neon, argon, krypton, xenon, and radon.
179
How many electrons do noble gases have in their outer energy level?
They all have eight electrons in their outer energy level
except helium, which has two.
180
What state do Group 0 elements exist in?
They exist as monatomic gases, meaning single atoms not bonded to each other.
-colourless gases at room temp
181
What is the flammability of noble gases?
Noble gases are non-flammable; they won't set on fire.
182
What happens to the boiling points of noble gases as you move down the group?
The boiling points increase increasing relative atomic mass.
183
What causes the increase in boiling points of noble gases?
due to an increase in the number of electrons in each atom
, leading to greater intermolecular forces between them which need to be overcome
184
How can you estimate the boiling point of a noble gas?
You can estimate it by knowing the boiling point of another noble gas in the group.
185
What is the predicted state of helium at 25 °C if neon is a gas at that temperature?
Helium must also be a gas at 25 °C since it has a lower boiling point than neon.
186
What is the predicted boiling point of xenon if radon and krypton have boiling points of -62 °C and -153 °C respectively?
Xenon's boiling point would be about -108 °C, halfway between radon and krypton.
