Unit 2 -atomic Structure

Question 1

Relative mass and charge of a proton

Answer 1

Charge = +1
Mass = 1

Question 2

Relative mass and charge of neutrons

Answer 2

Charge = 0 or neutral 
Mass = 1

Question 3

Relative mass and charge of electron

Answer 3

Charge = -1
Mass = 0.0005

Question 4

What is the atomic number of an element?

Answer 4

The number of protons in the nucleus (this is what defines an element).
Found at the bottom left of an element card

Question 5

What is the mass number of an isotope/element

Answer 5

The total number of protons and neutrons in a nucleus.

Found top left of an element card

Question 6

What is an isotope

Answer 6

The different forms of the same element that contain the same number of protons but different number of neutrons in the nucleus. They differ in relative atomic mass but not in chemical properties

Question 7

What is the relative atomic mass

Answer 7

The relative atomic mass of an element (Ar) is an average value of mass for the isotopes of the element compared to 1/12 of carbon (RAM 12)

Question 8

How to work out relative atomic mass of an element from the relative abundances of its isotopes

Answer 8

Add the percentages of each isotope.
Eg ISO1 = X mass, y% ISO2= A mass, B%

RAM = (X * Y/100) + (A * B/100)

Question 9

What does an atom consist of ?

Answer 9

Atoms consist of a central nucleus, composed of protons (+1) and neutrons (+/-0), surrounded by electrons (-1) in orbiting shells

Question 10

How many electrons can each shell hold ?

Answer 10

Maximum of 2 X n²
ie. 
Shell 1 = 2 e
Shell 2 = 8 e
Shell 3 = 18 e
Shell 4 = 32 e

Question 11

Number of electrons in a neutral atom =

Answer 11

Number of protons

Question 12

What is a cation

Answer 12

A positively charged ion
Has more protons than electrons
Cations are PUSSitive

Question 13

What is an anion

Answer 13

A negatively charged ion.

Has more electrons than protons

Question 14

How are ions formed

Answer 14

When a neutrally charged atom gains or loses electrons

Question 15

What is ionic bonding

Answer 15

Bonding between a metal and a non metal.
The metals lose electrons and give them to the non metals so that they can become stable (8 electrons in the outer shell).
This bonding is strong electrostatic attraction between oppositely charged ions

Question 16

What elements have stable electron arrangements (8 electrons in the outer shell)

Answer 16

Noble gasses

Question 17

Can you predict the charge of an ion from ionic bonding?

Answer 17

Yes. See how many electrons it has in its outer shell and see how many it needs to gain/lose in order to have 8 electrons in its outer shell.

Question 18

Do ionic compounds have high melting points?

Answer 18

Yes. Ionic compounds have high melting and boiling points because of the strong electrostatic attraction between oppositely charged ions.

Question 19

What is an ionic crystal

Answer 19

An ionic crystal is a three-dimensional lattice structure held together by attraction between oppositely charged ions

Question 20

What is electric currant

Answer 20

Electric current is the flow of electrons or ions

Question 21

In what state will ionic compounds conduct electricity

Answer 21

Ionic compounds will only conduct electricity when molten or in a solution

Question 22

Why do ionic compounds only conduct electricity when molten or in a solution

Answer 22

Because of the attraction between the anions and cations, the ions/electrons are not free to move in a solid state. However, when molten or dissolved, these ions are free to move

Question 23

What is a covalent bond

Answer 23

The sharing of a pair of electrons between two atoms in order to become stable.
Covalent bonding only happens in non-metals.
Covalent bonding is a strong attraction between the bonding pair of electrons and the nuclei of the atoms involved in the bond

Question 24

Do covalent compounds with simple molecular structures have high or low melting/boiling points

Answer 24

Covalent compounds have low melting/boiling points.
Even thought the covalent bonds are very strong, the molecules are held together by weak forces. Therefore, covalent compounds how low melting/boiling points

Question 25

What are substances with molecular structures

Answer 25

Solids, liquids, or gases with low melting points

Question 26

Do substances its giant covalent structures have high or low melting/boiling points

Answer 26

Giant covalent structures (giant lattice) have high melting/boiling points in terms of the breaking of so many strong covalent bonds

Question 27

Do covalent structures conduct electricity?

Answer 27

Covalent structures do not conduct electricity. This is because a covalent bond is formed between non metal atoms, which combine together by sharing electrons. Covalent compounds have no free electrons and no ions so they don't conduct electricity.

Question 28

What is a metal

Answer 28

A giant structure of positive ions surrounded by a sea of delocalised electrons

Question 29

Why do metals conduct electricity so well

Answer 29

Because of the sea of delocalised electrons, the electrons can flow easily forming an electric currant

Question 30

Are metals malleable

Answer 30

Yes. Metals can be bent and shaped because they consist of layers of atoms that can slide over one another when the metal is bent, pressed, or hammered

Question 31

Why would you use a flame test

Answer 31

The colour of the flame can be used to identify the group 1 or 2 element present in a compound

Question 32

How do you conduct a flame test

Answer 32

Use a clean rod made of platinum or silicone glass Dip rod in concentrated HCl and then then powdered substance Put it in the blue Bunsen burner flame Observe the colour of the flame

Question 33

What colour does the cation Li+ give in a flame test

Answer 33

Carmine red

Question 34

What colour does the cation Na+ give in a flame test

Answer 34

Intense yellow

Question 35

What colour does the cation K+ give in a flame test

Answer 35

Lilac

Question 36

What colour does the cation Ca++ give in a flame test

Answer 36

Brick red

Question 37

Properties of giant ionic lattices

Answer 37

``` Hard, brittle crystalline substances High melting/boiling points Soluble in water Insoluble in non-polar solvents Don't conduct electricity when solid but do when molten or dissolved in water ```

Question 38

Properties of covalent simple molecular lattices

Answer 38

``` Soft solids Low melting/boiling points Soluble in non-polar solvents but insoluble in water Don't conduct electricity in any state Made up of simple molecules ```

Question 39

Properties of giant covalent lattices

Answer 39

Hard (if 3D) or flakey (if 2D), crystalline solids Very high melting points Insoluble in most solvents Do not conduct electricity in any state (except graphite) Made up of atoms joined to each other by covalent bonds in an extended lattice

Question 40

Properties in giant metallic lattices

Answer 40

Hard High melting/boiling points (not with alkali metals) Malleable and ductile Conduct heat and electricity both solid and molten Soluble in liquid metals but not other solvents Reactive metals do react with water

Question 41

What is an ionic equation

Answer 41

Only the ions which changed state. Charge and state are included (often colour too)

Question 42

What is a group in the periodic table

Answer 42

A verticals column of elements which all have the same number of electrons in their outer shell and have fairly similar properties

Question 43

What is a period in the periodic table

Answer 43

A horizontal row of elements which have the same number of occupied shells of electrons