Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry > Atoms Elements And Compounds > Flashcards

Atoms Elements And Compounds Flashcards

(102 cards)

Start Studying
1
Q

What is an element?

A

A substance made of atoms that all contain the same number of protons and cannot be split into anything simpler.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a compound?

A

A pure substance made up of two or more elements chemically combined.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a mixture?

A

A combination of two or more substances (elements and/or compounds) that are not chemically combined.

Mixtures can be separated by physical methods such as filtration or evaporation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is atomic structure?

A

All substances are made of tiny particles of matter called atoms which are the building blocks of all matter. Each atom is made of subatomic particles called protons, neutrons, and electrons. The protons and neutrons are located at the centre of the atom, which is called the nucleus. The electrons move very fast around the nucleus in orbital paths called shells. The mass of the electron is negligible, hence the mass of an atom is contained within the nucleus where the protons and neutrons are located.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are protons, neutrons & electrons?

A

The size of atoms is so tiny that we can’t really compare their masses in conventional units such as kilograms or grams, so a unit called the relative atomic mass is used. One relative atomic mass unit is equal to 1/12th the mass of a carbon-12 atom. All other elements are measured relative to the mass of a carbon-12 atom, so relative atomic mass has no units.

Hydrogen for example has a relative atomic mass of 1, meaning that 12 atoms of hydrogen would have exactly the same mass as 1 atom of carbon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the relative mass of a proton?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the charge of a proton?

A

1+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relative mass of a neutron?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the charge of a neutron?

A

0 (neutral)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the relative mass of an electron?

A

1 over 1840

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the charge of an electron?

A

1-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the atomic number?

A

The number of protons in the nucleus of an atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the atomic number determine?

A

The position of the element on the Periodic Table.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the nucleon number?

A

The total number of protons and neutrons in the nucleus of an atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do you calculate the number of neutrons in an atom?

A

Nucleon number minus proton number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the mass number represent?

A

Mass number = number of protons + number of neutrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can you find the number of protons using mass number?

A

Number of protons = mass number – number of neutrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the relationship between protons and electrons in a neutral atom?

A

An atom is neutral and therefore has the same number of protons and electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can the number of neutrons in ions and atoms be calculated?

A

Number of neutrons = mass number – number of protons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do electrons orbit the nucleus?

A

Electrons orbit the nucleus in shells (or energy levels) and each shell has a different amount of energy associated with it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to the energy of a shell as it moves further from the nucleus?

A

The further away from the nucleus, the more energy a shell has.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do electrons fill the shells around the nucleus?

A

Electrons fill the shell closest to the nucleus. When a shell becomes full of electrons, additional electrons have to be added to the next shell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the maximum number of electrons the first shell can hold?

A

The first shell can hold 2 electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the maximum number of electrons the second shell can hold?

A

The second shell can hold 8 electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How many electrons can the third shell hold according to the simplified model used in this course?
For this course, a simplified model is used that suggests that the third shell can hold 8 electrons.
26
What happens when the third shell has 8 electrons for the first 20 elements?
Once the third shell has 8 electrons, the fourth shell begins to fill.
27
What do the red numbers at the bottom of the periodic table represent?
The red numbers at the bottom show the number of notations.
28
How many occupied shells does chlorine have?
The number of notations is 3, therefore chlorine has 3 occupied shells.
29
What does the last notation indicate about chlorine's outer shell?
The last notation, in this case 7, means that chlorine has 7 electrons in its outer shell.
30
In which group is chlorine located on the periodic table?
Chlorine is therefore in Group 7.
31
What is the outermost shell of most atoms like?
The outermost shell is not full.
32
Why do atoms react with other atoms?
To achieve a full outer shell of electrons, making them more stable.
33
What can atoms do to achieve a full outer shell?
Atoms can lose electrons to entirely empty the outer shell, allowing the next shell below to become the full outer shell.
34
What electronic structure do atoms achieve when they have a full outer shell?
They have the electronic structure of a noble gas (Group VIII).
35
What is the reactivity of noble gases?
All noble gases are unreactive as they have full outer shells and are very stable.
36
Layout of Atom
37
Atomic Structure
38
Shells of an atom
39
40
What are isotopes?
Isotopes are different atoms of the same element that contain the same number of protons but a different number of neutrons.
41
How are ions formed?
An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons. This loss or gain of electrons takes place to obtain a full outer shell of electrons.
42
What is the electronic structure of ions in Groups 1, 2, 6, and 7?
The electronic structure of ions of elements in Groups 1, 2, 6, and 7 will be the same as that of a noble gas - such as helium, neon, and argon.
43
What are negative ions called?
Negative ions are called anions and form when atoms gain electrons, meaning they have more electrons than protons.
44
What are positive ions called?
Positive ions are called cations and form when atoms lose electrons, meaning they have more protons than electrons.
45
How do metals become positively charged ions?
All metals lose electrons to other atoms to become positively charged ions.
46
How do non-metals become negatively charged ions?
All non-metals gain electrons from other atoms to become negatively charged ions.
47
What is ionic bonding?
Ionic compounds are formed when metal atoms react with non-metal atoms. Metal atoms lose their outer electrons which the non-metal atoms gain to form positive and negative ions.
48
What holds ionic compounds together?
The positive and negative ions are held together by strong electrostatic forces of attraction between opposite charges. This force of attraction is known as an ionic bond.
49
What is the state of ionic compounds at room temperature?
Ionic compounds are usually solid at room temperature.
50
What are the melting and boiling points of ionic compounds?
They have high melting and boiling points.
51
How do ionic compounds conduct electricity?
Ionic compounds are good conductors of electricity in the molten state or in solution, but poor conductors in the solid state.
52
How are covalent compounds formed?
Covalent compounds are formed when pairs of electrons are shared between atoms.
53
Which elements participate in covalent bonding?
Only non-metal elements participate in covalent bonding.
54
What happens to the electron configuration in covalent bonding?
Each atom gains a full outer shell of electrons, giving them a noble gas electronic configuration.
55
What do covalently bonded substances consist of?
Covalently bonded substances may consist of small molecules or giant molecules.
56
What do we call two or more atoms that are covalently bonded together?
We describe them as ‘molecules’.
57
What is a dot-and-cross diagram?
Dot-and-cross diagrams can be used to show the electronic configurations in simple molecules.
58
How are electrons represented in a dot-and-cross diagram?
Electrons from one atom are represented by a dot, and the electrons of the other atom are represented by a cross.
59
What does the overlap of electron shells in a molecule indicate?
The electron shells of each atom in the molecule overlap and the shared electrons are shown in the area of overlap.
60
What does a dot-and-cross diagram show?
The dot-and-cross diagram of the molecule shows clearly which atom each electron originated from.
61
What are covalent compounds?
Covalent compounds are formed when pairs of electrons are shared between atoms.
62
Which elements participate in covalent bonding?
Only non-metal elements participate in covalent bonding.
63
What do atoms gain from covalent bonding?
Each atom gains a full outer shell of electrons, giving them a noble gas electronic configuration.
64
What do we call substances formed by covalent bonds?
When two or more atoms are covalently bonded together, we describe them as ‘molecules’.
65
What types of molecules can covalently bonded substances consist of?
Covalently bonded substances may consist of small molecules or giant molecules.
66
What are dot-and-cross diagrams used for?
Dot-and-cross diagrams can be used to show the electronic configurations in simple molecules.
67
How are electrons represented in dot-and-cross diagrams?
Electrons from one atom are represented by a dot, and the electrons of the other atom are represented by a cross.
68
What happens to the electron shells in a covalent bond?
The electron shells of each atom in the molecule overlap and the shared electrons are shown in the area of overlap.
69
What does a dot-and-cross diagram show?
The dot-and-cross diagram of the molecule shows clearly which atom each electron originated from.
70
Ionic Bonding (Image)
71
Chlorine Ionic Bonding (image)
72
Sodium Chloride Ionic Bonding (image)
73
Ionic bonding (image 2)
74
Covalent Bonding (Image)
75
What are small molecules?
Small molecules are compounds made up of molecules that contain just a few atoms covalently bonded together.
76
What are the melting and boiling points of covalent compounds?
They have low melting and boiling points, so covalent compounds are usually liquids or gases at room temperature.
77
How do the melting and boiling points change with molecule size?
As the molecules increase in size, the melting and boiling points generally increase.
78
What is the electrical conductivity of small molecules?
Small molecules have poor electrical conductivity.
79
Why are molecular compounds poor conductors of electricity?
Molecular compounds are poor conductors of electricity as there are no free ions or electrons to carry the charge.
80
Do covalent compounds conduct electricity in solid state?
Most covalent compounds do not conduct at all in the solid state and are thus insulators.
81
What are common insulators?
Common insulators include the plastic coating around household electrical wiring, rubber, and wood.
82
What is the structure of graphite?
Each carbon atom in graphite is bonded to three others forming layers of hexagons, leaving one free electron per carbon atom which becomes delocalised.
83
What type of forces exist between layers in graphite?
The covalent bonds within the layers are very strong, but the layers are attracted to each other by weak intermolecular forces.
84
What are diamond and graphite in terms of structure?
Diamond and graphite are allotropes of carbon which have giant covalent structures.
85
How do diamond and graphite differ physically?
Both substances contain only carbon atoms, but due to the differences in bonding arrangements, they are physically completely different.
86
What is a giant covalent structure?
Giant covalent structures contain billions of non-metal atoms, each joined to adjacent atoms by covalent bonds forming a giant lattice structure.
87
What is the structure of diamond?
In diamond, each carbon atom bonds with four other carbons, forming a tetrahedron.
88
What are the properties of covalent bonds in diamond?
All the covalent bonds are identical, very strong, and there are no intermolecular forces.
89
What are the properties and uses of graphite?
Graphite conducts electricity, has a high melting point, and is slippery due to its layered structure.
90
How does graphite conduct electricity?
Each carbon atom is bonded to three others, leaving one free electron per carbon atom that can move through the structure and carry charge.
91
Why is graphite used in pencils?
Graphite is slippery and arranged in layers, allowing the layers to slide over each other.
92
What makes graphite a good industrial lubricant?
The weak intermolecular forces between the layers allow them to slide over each other, making graphite slippery.
93
Does diamond conduct electricity?
Diamond does not conduct electricity.
94
Why doesn't diamond conduct electricity?
All the outer shell electrons in carbon are held in the four covalent bonds around each carbon atom. As a result, there are no freely moving particles to carry a charge.
95
What is the melting point of diamond?
Diamond has a very high melting point.
96
What type of structure does diamond have?
Diamond has a giant covalent structure.
97
What type of bonds are present in diamond?
There are strong covalent bonds between the carbon atoms.
98
Why does diamond have a high melting point?
The strong covalent bonds need lots of energy to break.
99
What are the physical properties of diamond?
Diamond is extremely hard and dense.
100
How is diamond's hardness useful?
Diamond's hardness makes it very useful in cutting tools like drills.
101
Graphite Covalent Bonding
102
Diamond Covalent Bonding

Chemistry (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions