Atomic Structure

Question 1

Atom Size

Answer 1

Atoms are very small, having a radius of about 0.1 nm (1 x 10-10 m)

Question 2

Lithium and Water

Answer 2

When lithium is added to water, lithium floats. It fizzes steadily and becomes smaller, until it eventually disappears.

Question 3

Sodium and Water

Answer 3

When sodium is added to water, the sodium melts to form a ball that moves around on the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.

Question 4

Potassium and Water

Answer 4

When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.

Question 5

Transition Metals and Oxygen

Answer 5

Most transition elements react slowly, or not at all, with oxygen at room temperature. Some transition metals react with oxygen on heating

Question 6

Transition Metals and Water

Answer 6

The group 1 elements react vigorously with cold water. Most transition elements react slowly with cold water, or not at all.

Iron reacts with water and oxygen at room temperature to form hydrated iron(III) oxide, or rust.

Question 7

Transition Metals and Halogens

Answer 7

The group 1 elements react vigorously with the halogens. Some transition elements also react with halogens

Question 8

Filtration

Answer 8

1. One beaker contains a mixture of solid and liquid, the other contains a funnel with filter paper
2. The solid and liquid mixture is poured into the filter funnel
3. The liquid drips through the filter paper but the solid particles are caught in the filter paper

Question 9

Simple Distillation

Answer 9

1. Salty water is heated
2. The water vapour cools in the condenser and drips into a beaker
3. The water has condensed and is now in the beaker, the salt stays behind

Question 10

Chromatography

Answer 10

1. Spots of ink or plant dye are placed on a pencil line
2. As the paper is lowered into the solvent, some of the dye spreads up the paper
3. The paper has absorbed the solvent, and the dye has spread further up the paper

Question 11

Retardation Factor

Answer 11

Rf = distance moved by the compound ÷ distance moved by the solvent