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Flashcards in Key Concepts In Chemistry Deck (81):
1

What does (s) mean

Solid

2

What does (l) mean

Liquid

3

What does (g) mean

Gas

4

What does (aq) mean

Aqueous - dissolves in water

5

What is the formula for water

H20

6

What is the formula for carbon dioxide

CO2

7

What is the formula for chlorine

Cl2

8

What is the formula for ammonia

NH3

9

What is the formula for hydrogen

H2

10

What is the formula for oxygen

O2

11

What is the ionic formula for ammonium

NH4+

12

What is the ionic formula for nitrate

NO3-

13

What is the ionic formula for sulfate

SO42-

14

What is the ionic formula for hydroxide

OH-

15

What is the ionic formula for carbonate

CO32-

16

What is a hazard

Anything that has the potential to cause harm or damage

17

What is a risk

the probability of someone (or something) being harmed if they are exposed to the hazard

18

What are the 3 subatomic particles

Protons, neutrons and electrons

19

What are the properties of protons

Heavy and positively charged

20

What are the properties of electrons

Heavy and neutral

21

What are the properties of neutrons

Hardly any mass and are negatively charged

22

Describe the nucleus of an atom

In the centre of an atom
Contains protons and neutrons
Has a positive charge because of the protons
It is where almost all of the atoms mass is
It is tiny compared to the overall size of the atom

23

Describe the electrons of an atom

Move around the nucleus in electron shells
Negatively charged
Tiny but their shells cover a lot of space
The size of their shells determines the size of the atom
They have a tiny mass

24

Describe the properties of atoms

Have the same number of protons as electrons
They are neutral (no charge)
The charge on the electrons is the same size as the charge on the protons but opposite so the charges cancel out

25

What does the nuclear symbol of an atom tell you

Its mass number and atomic number

26

What does the atomic number tell you

How many protons an atom has

27

What does the mass number tell you

The total number of protons and neutrons

28

What are isotopes

Different forms of the same element, which have the same number of protons but a different number of neutrons
Same atomic number but different mass numbers
Eg. Carbon-12 and Carbon-13

29

Who made the first periodic table

Dimitri Mendeleev

30

What are the electron shell rules

2,8,8 and the lowest energy levels are always filled first

31

What are ions

Charged particles that can be single atoms or groups of atoms

32

What is an anion

A negative ion

33

What is a cation

A positive ion

34

How do negative ions form

When atoms gain electrons

35

How do positive ions form

When atoms lose electrons

36

What groups are most likely to form ions

Group 1, 2, 6, 7

37

What are ionic compounds made up of

A positively charged part and a negatively charged part

38

What is the overall charge of any ionic compound

Zero

39

What is an ionic bond

When a metal and a non-metal reacts together.
The metal loses electrons to form a positive ion and the non-metal gains electrons to form a negative ion.
These are strongly attracted to each other with an electrostatic force

40

What do dot and cross diagrams show

The arrangement of electrons in an atom or ion

41

What do ionic compounds always have

Giant ionic lattice structures

42

What are the properties of ionic compounds

High melting and boiling point
Solid ionic compounds cannot conduct electricity
Melted ionic compounds can conduct electricity
Dissolve easily in water

43

Why do ionic compounds have high melting and boiling points

Due to their strong attraction between the ions. It takes a large amount of energy to overcome this attraction

44

Why don’t solid ionic compounds conduct electricity but melted ionic compounds do

Because in a solid, the ions are fixed in place and cant move but when melted, the ions are free to move and will carry an electric current

45

Why do ionic compounds dissolve easily in water

The ions separate and are free to move in the solution so they’ll carry an electric current

46

What are the advantages of showing ionic compounds in 2D representations

They are great at showing what atoms something contains and how the atoms are connected

47

What are the disadvantages of 2D representations of ionic compounds

They don’t show the shape of the substance and they don’t give you any idea about the sizes of the atoms

48

What are the advantages of a dot and cross diagram

They are useful for showing how compounds or molecules are formed and where the electrons in the bonds or ions came from

49

What are the disadvantages of dot and cross diagrams

They don’t usually show anything about the size of the atoms or ions or how they are arranged

50

What are the advantages of 3D models showing structures

They show the arrangement of atoms

51

What are the disadvantages of 3D models showing structures

They only show the outer layer of a substance

52

What are the advantages of a ball and stick model

Helps to visualise structures as they show the shape of the lattice or molecule in 3D
They’re more realistic

53

What are the disadvantages of ball and stick models

They don’t show the correct scales of the atoms or ions

54

What is a covalent bond

A strong bond when a pair of electrons is shared between two atoms

55

What are simple molecular substances made up of

Molecules containing a few atoms joined by covalent bonds

56

What do you need to do to melt or boil a simple molecular compound

Break the feeble intermolecular forces and not the covalent bonds

57

Do molecular compounds conduct electricity and why

No because they haven’t got any free flowing electrons or ions

58

What are the properties of giant covalent structures

Strong covalent bonds between each atom
High melting and boiling point - lots of energy needed to break the bonds
Don’t contain charged particles - don’t conduct electricity
Aren’t soluble in water

59

What are 3 examples of carbon-based giant covalent structures

Diamond
Graphite
Graphene

60

What is diamond made up of

Carbon atoms that each form 4 covalent bonds

61

Does diamond have a high or low melting point

High

62

Is diamond hard or soft, why

Hard because the strong covalent bonds hold the atoms in a rigid lattice structure

63

Does diamond conduct electricity

No because it has no free electrons or ions

64

In graphite, how many covalent bond does a carbon atom form, what does it create

3, creating sheets of carbon atoms arranged in hexagons

65

Is graphite hard or soft, why?

Soft and slippery because there aren’t any covalent bonds between the layers so they’re held together weakly and free to move over each other

66

Can graphite conduct electricity

Yes as only 3 out of 4 electrons are used in bonds so each carbon atom has 1 electron that’s delocalised (free)

67

What is the structure of graphene

1 layer of graphite
A sheet of carbon atoms joined together in hexagons

68

Are the electrons in the outer shell of metal atoms localised or delocalised

Delocalised

69

What is metallic bonding

The forces of attraction between the positive metal ions and the shared negative electrons hold the atoms together in a regular structure.

70

What is the relative formula mass (RFM)

The relative atomic masses of all the atoms added together

71

What does the empirical formula of a compound tell you

The smallest whole number ratio of atoms in a compound

72

How do you calculate the molecular formula

Add the empirical formula and the relative formula mass

73

What is a mole

The name given to a certain number of particles

74

What is a mole equal to

A number called Avogrado’s constant

75

What is the number of Avogrado’s constant

6.02 x10 to the power of 23

76

Why is Avogrado’s constant useful

Because when you get the number of atoms or molecules, of any element or compound, then they weigh the same number of grams as the RAM/RFM of the element or compound

77

What is the equation for the number of moles

Number of moles = mass in g (of element or compound) / RFM of compound or RAM of element

78

What is the formula triangle involving mass, moles and RFM

Mass
—————-
Moles x RFM

79

What is the equation for concentration

Concentration = mass of solute / volume of solution

80

When do reactions stop

When all of one reactant is used up

81

What is the limiting reactant

The reactant that is used up in the reaction