Lithium

Sodium

Potassium

Rubidum

Caesium

Francium

• Lithium (Li)

• Sodium (Na)

• Potassium (K)

• Rubidium (Rb)

• Caesium (Cs)

• Francium (Fr)

Na

K

Rb

Cs

Fr

Sodium

Potassium

Rubudium

Caesium

Francium

Na

K

Rb

Cs

Fr

sodium

potassium

rubidium

casium

francium

Sodium

Potassium

Rubidium

Caesium

Francium

​Sodium

​Potassium

​Rubidium

​Cesium

​Francium

Sodium is also soft and shiny, and you can cut it easily with a knife. When it reacts with water, it melts into a small ball and moves quickly across the surface while fizzing more than lithium. The solution formed is strongly alkaline, with a pH of about 13 to 14. It has one electron in its outer shell.

Potassium is even softer and reacts more vigorously. When it is added to water, it reacts very fast and produces a lilac flame, which makes it easy to recognize. The solution formed is very alkaline, with a pH close to 14. It also has one electron in its outer shell.

Rubidium is extremely reactive and very soft. When it comes into contact with water, the reaction is so violent that it can explode. The solution formed is strongly alkaline with a pH of about 14. Like the others, it has one electron in its outer shell.

As you go down the group, the metals become more reactive.

They are called alkali metals because they form alkaline solutions when they react with water.

They all react in a similar way because they each have one electron in their outer shell.

These metals are stored in oil to stop them from reacting with air or moisture.

Some other properties are that they are soft, have low density, have relatively low melting points, and are very reactive.

(a) State the approximate percentage of each of these four gases in dry air.
(b) Explain why air is a mixture and not a compound.
(c) Name one gas that may be present in unpurified air but not in dry air.

b) Air is a mixture because the gases are not chemically combined and can be present in different proportions.

(c) Water vapour

nitrogen=78%

argon=0.9%

carbon dioxide=0.04%

2)its a mixture because the gasses are not chemically combine

3)water vapor

• Nitrogen: 78%

• Oxygen: 21%

• Argon: 1%

• Carbon dioxide: 0.04%

(b)
Air is a mixture because the gases are mixed, not joined, and you can separate them.

(c)
Water vapor

(b) Air is a mixture because gases are not chemically combined

(c) Water vapour

Nitrogen 78%

Oxygen 21%

2 the gasses are not physically bonded

3 water vapor

(b) Air is a mixture because its components are not chemically bonded, can be separated by physical methods, and have variable proportions.

(c) Water vapor (humidity)

oxygen= 21%

argon =0.9%

Carbon dioxide= 0.04

becease different types of moelclues are to gether and their not chemically bond

water vapour

b) No chemical bonding, the gases in the air are not chemically joined together, they simply move around each other.

c) Water vapor.

Oxygen - 21%

Argon - 1%

CO2 - 0.04%

B) Ais is a misture of gases they are not chemically bonded

C) Water Vapour

oxygen=20%

Argon=0.9%

CO2= 0.05%

B) because gases are not joined and u can separate them

Oxygen 21%

Argon 0.9%

Carbon dioxide 0.04%

B) air is a mixture because the gasses are physically mixed together not chemically bonded

C) water vapor

b) air isn't a mixture, so the gases are not chemically not bonded to eachother.

c) Water vapor

(b) oxygen

(c) The oxygen is used up during the reaction.

(d) The oxygen being consumed creates a lower pressure inside the jar, allowing atmosphere pressure to push the water up. (e) 20.8%

(b)

Oxygen

(c)

The volume decreases because oxygen is used up during the reaction.

(d)

Water rises because oxygen is removed from the air, reducing pressure inside the jar, so water moves up to fill the space.

(e)

Initial volume = 120 cm³

Final volume = 95 cm³

Oxygen used = 120 − 95 = 25 cm³

Percentage of oxygen = (25 ÷ 120) × 100 = 20.8% (≈ 21%)

b) Oxygen.

c) The volume decreases because the oxygen in the air is used up as it reacts with the phosphorus to form a solid (phosphorus oxide). Since the oxygen is removed from its gaseous state, there is less gas remaining in the jar.

d) As the oxygen is consumed, the pressure in the jar decreases and becomes lower than the atmospheric pressure outside. This pressure difference pushes water up into the jar to occupy the space previously taken up by the oxygen.

e) 25/120 × 100 = 20.8%.