chem

Answer 1

Lithium has the electron structure (2,1).
Lithium is the least reactive of the alkali metals.
Lithium burns with a crimson flame when it reacts with oxygen.
Lithium floats on the surface of water and will release bubbles of hydrogen gas (it effervesces).

Answer 2

Sodium has the electron structure (2,8,1).
Sodium is more reactive than lithium because its outer electron is less strongly attracted to the positively charged nucleus. This is because it is a greater distance from the positive charge of the atom’s nucleus.
The metal floats on the surface of water, which releases enough heat to melt the sodium. The sodium moves quickly across the surface of the water.
Sodium burns with a yellow/orange flame when it reacts with oxygen.

Answer 3

Potassium has the electron structure (2,8,8,1).
Potassium is more reactive than lithium and sodium because its outer electron is least strongly attracted to the nucleus.
The metal floats on the surface of water, and has a similar, but more vigorous, reaction compared with sodium.
Potassium burns with a lilac flame when it reacts with oxygen.

Answer 4

Lithium
Sodium
Potassium

All group 1 (and group 2) elements end with ium.

Answer 5

Reacting with chlorine

A metal chloride is formed (e.g. sodium chloride), which dissolves in water to give a colourless solution.

Answer 6

Reacting with water

The metal floats on the surface and melts to create a metal hydroxide (e.g. lithium hydroxide).
When they react with water, the energy released is enough to melt the metal.

Answer 7

Reacting with oxygen

Rapidly turns from silvery shiny to dull as a metal oxide (e.g. potassium oxide) is produced.

Answer 8

Lithium
Fizzes steadily and floats, becoming smaller until it eventually disappears.

Sodium
Fizzes rapidly and melts to form a ball that moves around on the water surface.

Potassium
The hydrogen produced ignites instantly and the metal also sets alight, sparking and burning with a lilac flame.

Answer 9

As you go down group 1 of the periodic table, the reactions become:

1
Quicker
2
More vigorous

Question 10

Reactions of reactive metals with water

Answer 10

metal+water
→
metal hydroxide+hydrogen

Answer 11

Particles in liquids are very close together but they move and flow randomly past one another.
2
Particles in liquids have a fixed volume but can change shape to fill a container.

Answer 12

Ionic compounds form giant structures called ionic lattices that are held together by strong electrostatic forces of attraction between positive and negative ions. These forces are called ionic bonds.

Question 13

Ionic compounds made from how many different elements end in -ide?

Answer 13

2