atomic structure and periodic table

Question 1

Why do the elements get more reactive as you go down Group 1?

Answer 1

• they lose their outer single electron
  -this is easier as you go down the group:
  -the outer electron gets further from the positive nucleus and so it feels less of an attractive force and can leave easier
  -as you go down the group there are more electron shells between the nucleus and the outer electron, this lowers the attraction force.

Question 2

A Group 1 metal reacts with water. What is produced?

Answer 2

hydrogen and an alkaline solution of metal hydroxide.

Question 3

What happens when lithium reacts with water?

Answer 3

Floats, fizzes.

Question 4

What happens when sodium reacts with water?

Answer 4

moves around the surface and gets hot enough to melt.

Question 5

What happens when potassium reacts with water?

Answer 5

whizzes around the surface and melts, burns a lilac flame due to the hydrogen.

Question 6

What happens if rubidium reacts with water?

Answer 6

violently, everything leaves the container

Question 7

What happens if calcium reacts with water?

Answer 7

explodes on contact with water, possibly shattering the container

Question 8

What is a displacement reaction?

Answer 8

a chemical reaction where a more reactive elements displaces a less reactive element from its compound.

Question 9

What is a halide?

Answer 9

compound formed between a halogen and another element.

Question 10

what is a (a) method, (b) apparatus and (c) example of the mixture: separating an insoluble solid from a liquid.

Answer 10

(a) filtration because the insoluble solid cannot pass through the filter paper.
(b) filter funnel, filter paper, funnel.
(c) insoluble sand from water

Question 11

what is a (a) method, (b) apparatus and (c) example of the mixture: separating two or more miscible liquids.

Answer 11

(a) fractional distillation because the liquid with the higher BP condenses on the column, the liquid with the lower BP carries on up as a vapour.
(b) flask, heating equipment, fractionating column, condenser
(c)

Question 12

what is a (a) method, (b) apparatus and (c) example of the mixture: separating the liquid from a solution of a solution of a solid in a liquid. the liquid is distillate.

Answer 12

(a) simple distillation because the liquid has a much lower boiling point and so evaporates at a much lower temperature.
(b) flask, heating equipment, condenser.
(c) water from salty water.

Question 13

what is a (a) method, (b) apparatus and (c) example of the mixture: separating the dissolved solid from a solution.

Answer 13

(a) crystallisation which depends on big differences in boiling points between solvent and the dissolved solid.
(b) evaporating basin, heating equipment
(c) heated to make a crystal

Question 14

what is a (a) method, (b) apparatus and (c) example of the mixture: separating coloured substances

Answer 14

(a) paper chromatography which relies on the substances having different attractions for the paper and solvent
(b) container, chromatography paper
(c) separate mixtures of coloured compounds

Question 15

What were Joseph John Thompson’s contributions

Answer 15

• discovered the electron
  -suggested the plum pudding model

Question 16

What were Ernest Rutherford’s contributions

Answer 16

• found the central nucleus which contained positive charged atoms with electrons orbiting around it

Question 17

What did James Chadwick discover?

Answer 17

• the neutron apart of the nucleus

Question 18

What did John Dalton first suggest?

Answer 18

-solid spheres, all different types.

Question 19

What was Rutherford’s most important experiment?

Answer 19

-fired high energy charged alpha particles at a gold foil
-they observed some passed through whilst some deflected off
-the nucleus must be positive to repel the alpha particles and very dense because it had to withstand its energy
-as most of the alpha particles passed through, there must be empty space.

Question 20

Who first developed the periodic table?

Answer 20

Mendeleev

Question 21

How did Mendeleev first organise the table?

Answer 21

in order of atomic weights, similar properties in groups, left spaces for undiscovered elements.

Question 22

How are elements organised now?

Answer 22

by their atomic number

Question 23

Why do atoms have no overall charge?

Answer 23

they have an equal number of positive and negative atoms.

Question 24

How does the loss or gain of electrons produce an ion?

Answer 24

A negative ion is formed if an atom gains an electron and a positive ion is formed if an atom loses an electron. Atoms form ions to gain a full outer shell of electrons.

Question 25

How to calculate the relative atomic mass of an element given the percentage of abundance

Answer 25

Multiply the % abundance of each isotope by its mass.
Add these numbers together.
Divide by the total abundance (which when using % abundance, will be 100%)

Question 26

How do properties of group 0 elements relate to outer shell arrangement

Answer 26

The atoms of each group 0 element have a full outer shell (highest occupied energy level). They have stable electronic configurations – they have no tendency to lose, gain or share electrons.