GCSE….

Question 1

ions

Answer 1

-ions: Electrically charged atom formed by loosing or gaining electrons.
-Takes place to obtain a full outer shell .
- cations +ve loosing ē, anions -ve gaining ē.
-All metals lose electrons = become +ve charged
- Non metals gain electrons = become -ve charged

Question 2

Dot & cross diagrams

Answer 2

-These show the arrangement of the electrons in an ionic compound.
-electrons shown as dots and cross
-charge written in top right hand corner outside bracket

Question 3

Ionic bonding

Answer 3

-metal + non-metal
-can be represented by dot and cross
-ions…..

Question 4

Ionic compounds

Answer 4

-A giant structure of ions
-held together by strong electrostatic forces of attraction between oppositely charged ions.
- since the structure is in 3D, the forces act in every direction.

Question 5

Covalent bonding

Answer 5

• non metal + non metal
  -atoms sharing one or more pairs of electrons.
  -polymers are large covalently bonded molecules
  -giant covalent structures consist of many atoms covalently bonded in a lattice structure. Eg diamond, silicon dioxide.
  Dot and cross.

Question 6

Metallic bonding

Answer 6

-Metal + metal
- positive ions and delocalised electrons arranged in a regular pattern.
-delocalized ē free to move through the structure , free to carry the charge around.
- strong as its shared across the structure.

Question 7

Relative atomic mass

Answer 7

Weighted mean mass of an atom of an element compared to the 1/12 of the mass of atom of carbon -12

Question 8

Percentage yield

Answer 8

Amount of product produced / maximum amount of product possible x 100

Question 9

Atom economy

Answer 9

(Mr of desired product from reaction/ sum of Mr of all reactants ) x 100

Question 10

Group 1

Answer 10

-Alkali metals
-single electron in their outer shells
-reach vigorously with water to create an alkaline solution and hydrogen.
-all react with oxygen to make oxide
- reach with chlorine = white precipitation
-reactivity increases down the group

Question 11

Exothermic reactions

Answer 11

-transfers energy to the surroundings so temp increases. Eg : combustion
Reactants - up products down

Question 12

Endothermic reactions

Answer 12

Takes in energy from the surroundings decreasing the temp
Eg ice pack
Reactants down , products up

Question 13

Activation energy

Answer 13

Activation energy: minimum amount of energy That particles must have to react

Question 14

Collision theory

Answer 14

Chemical reactions can only occur when reacting particles collide with each other and with sufficient energy.

Question 15

Rate

Answer 15

Amount of reactant/ product used divided by time

Question 16

Factors that affect the rate

Answer 16

Concentration, pressure , surface area , temperature and catalyst

Question 17

Increasing the concentration, pressure in gas and surface area of solid reactants …

Answer 17

Will increase the frequency of collisions so rate increases

Question 18

Temperature increases

Answer 18

The frequency of collisions increases and makes more collisions more energetic and so rate increases

Question 19

Catalyst

Answer 19

Biological substances that speed up the chemical reactions within being used up
Enzymes act as a catalyst
Rate increase as it speeds up the reaction