Handbook 1

Question 1

What is the maximum number of electrons which can occupy a

i) 2p sublevel
ii) 2 p orbital

Answer 1

i) 6

ii) 3

Question 2

Name the group on the periodic table whose elements are non-metallic and have a valency of 1

Answer 2

Group VII - Halogens

Question 3

Define the term valency

Answer 3

Number of electrons that can be gained, lost or shared

Question 4

What colour do Lithium salts give a Bunsen burner flame

Answer 4

Crimson/red

Question 5

What colour do copper salts give a Bunsen Burner flame

Answer 5

Blue-green

Question 6

Name the element that emits a yellow light during a flame test

Answer 6

Sodium

Question 7

What do E2 and f represent in the equation E2-E1=hf

Answer 7

E2- Higher energy level

f- frequency of light

Question 8

Distinguish between the terms ground and excited state

Answer 8

Ground state- Lowest available energy level

Excited-state- Higher available energy level

Question 9

Distinguish between the terms atomic number and mass number

Answer 9

Atomic number- Number of protons

Mass number- Number of protons and neutrons

Question 10

What does Aufbau’s principle state

Answer 10

When building up the electron configuration for an atom in its ground state the electrons occupy the lowest available energy level

Question 11

List two limitations of Bohr’s theory

Answer 11

Electrons move in a wave motion

Heinsberg’s uncertainty principle

Question 12

Distinguish between an atom and a compound

Answer 12

Atom is the smallest particle that has properties of an element
A compound is two or more elements that are chemically combined

Question 13

What are isotopes

Answer 13

Atoms of the same element with the same atomic number and different atomic mass

Question 14

What is an atomic orbital

Answer 14

A region of space where electrons are most likely to be found

Question 15

Outline the procedure of flame test

Answer 15

• Soak a wooden splint in water
• Dip it in salt
• Hold in the blue part of the Bunsen flame
• Observe colour

Question 16

What colour would Pottasium be in the flame test

Answer 16

Lilac

Question 17

What colour did Lithium salts give to a Bunsen burner flame

Answer 17

Crimson

Question 18

Explain why the second ionisation energy of an element is always higher than its first ionisation energy

Answer 18

Second electron is removed from a positive ion

Question 19

Define relative atomic mass

Answer 19

Mass of an atom compared to1/12th the mass of carbon 12- isotope

Question 20

Name two molecular crystals

Answer 20

Dry ice

Iodine

Question 21

2 Chemical properties associated with transition metals

Answer 21

• Variable valency

- Acts as a catalyst

Question 22

Define Heinsberg’s uncertainty principle

Answer 22

It is impossible to measure both the velocity and the position of an electron at the same time

Question 23

Define the first ionisation energy of an element

Answer 23

The minimum energy required to remove the most loosely bound electron from a neutral gaseous atom in its ground state

Question 24

The general rule for first ionisation energy across a periodic table

Answer 24

• IE value increases
• Atomic radius is decreasing
• Effective nuclear charge is increasing
• Screening effect remains the same

Question 25

explain why fi value of beryllium is larger than that of boron

Answer 25

Be- has a higher value as it has a full s-sublevel (2s2) and is stable B- Has a lower value as the p-sublevel is (2p) and is not stable

Question 26

Define Ionic bond

Answer 26

The force of attraction between oppositely charged ions due to the transfer of electrons

Question 27

Describe the crystal structure of sodium chloride

Answer 27

Crystal lattice Sodium ions are surrounded by 6 chloride ions Each chloride ion is surrounded by 6 sodium ions

Question 28

Give two general properties of ionic compounds

Answer 28

- Conduct electricity when dissolved in water - Form solid crystal lattice structures - Compound of ions - Have high melting or boiling points

Question 29

Define intermolecular forces

Answer 29

Force of attraction between molecules

Question 30

Name the type of intramolecular bonding in i) Ammonia gas ii) Water iii) Methane gas

Answer 30

i) Hydrogen Bonding ii) Hydrogen bonding iii) Van der waals

Question 31

Explain in terms of intermolecular forces why NH3 is very soluble in water

Answer 31

- NH3 is a polar molecule - H2O is a polar molecule - Positive side of the H20 attracts the negative side of the NH3 molecule - The negative side of the H20 attracts the positive side of the NH3 "Like dissolves like"

Question 32

Describe the bonding in Cl2

Answer 32

Pure covalent bond

Question 33

Define electronegativity

Answer 33

The measure of the force of attraction an atom has for a shared pair of electrons in a covalent bond

Question 34

Why do electronegativity values increase across the third period of the periodic table

Answer 34

- Atomic radius decreases - Electric nuclear change increases - Screening effect remains the same