Topic 1

Question 1

explain in terms of subatomic particles what is meant by an isotope

Answer 1

two or more forms of the same element with equal number of protons and different number of neutrons meaning they have different relative masses

Question 2

using information in figure four (dot and cross of calcium with 4 outer shells) explain which period of the periodic table calcium can be found

Answer 2

period 4 because the period number is the number of outer shells and calcium has four outer shells

Question 3

a chlorine atom contains 17 electrons, 18 neutrons and 17 protons

a) state mass number
b) give electronic configuration

Answer 3

a) mass number - 32

b) electronic configuration - 2,8,7

Question 4

potassium and caesium are in the same group.

explain in terms of electrons why potassium and caesium are in the same group.

Answer 4

both have one electron in their outer shell and lose one electron in a reaction to form positively charged ions

Question 5

nickel is a metal. explain how the structure of a nickel atom changes when it forms a nickel ion, N2+

Answer 5

loss of two electrons

Question 6

metals have high melting points. explain in terms of their structure and bonding why metals have high melting points

Answer 6

strong electrostatic forces of attraction between positive ions and negative electrons. more energy is needed to overcome the forces

Question 7

covalent structures can be simple molecular or giant covalent. ammonia is a simple molecular covalent substance which is the most likely set of properties for ammonia?

A) melting point - 1713, boiling point - 2950, does not conduct electricity
B) melting point - -78, boiling point - -33, does not conduct electricity
C) melting point - -39 , boiling point - 357, does conduct electricity
D) melting point - 801 , boiling point - 1413, does conduct electricity

Answer 7

B - melting point - -78, boiling point - -33, does not conduct electricity

Question 8

ammonia is made by reacting nitrogen with hydrogen. write the balanced equation for this reaction.

Answer 8

N2 + 3H2 —> 2NH3

Question 9

describe what is meant by a covalent bond

Answer 9

shared pair of electrons between atoms

Question 10

explain why chlorine is a gas, rather than a liquid, at room temp

Answer 10

weak intermolecular forces require less energy to break, so boiling point is below room temperature (low)

Question 11

explain why carbon dioxide has a low boiling point

Answer 11

there are weak intermolecular forces between particles so less heat energy is needed to overcome these. the covalent bonds aren’t broken

Question 12

the ions present in sodium sulfate are

sodium - Na+
sulfate - SO4 2-

write a formula of sodium sulfate using this information

Answer 12

Na2SO4

Question 13

element X has an atomic number of 18.

state the electronic configuration of an atom of element X

Answer 13

2, 8, 8

Question 14

some of the elements in the periodic table are metals. the electronic configuration of a metal is 2,8,3

which row shows the group and period of the periodic table where this metal is found?

A) group 2, period 3
B) group 2, period 8
C) group 3, period 2
D) group 3, period 3

Answer 14

D) group 3, period 3

Question 15

7. 59% of lithium-6
8. 41% of lithium-7

calculate the relative atomic mass of lithium in this sample to 2 d.p

Answer 15

(7.59 x 6) + (92.41 x 7) / 100

= 6.9241

= 6.92