Group 1 elements

Question 1

What are group 1 elements known as?

Answer 1

Alkali metals

Question 2

Give 3 physical properties of the group 1 elements.

Answer 2

• Soft (can be cut with a knife.)
• low melting point (decreases as you go down)
• Low density

Question 3

What is the melting point of alkali metals?

Answer 3

• Low melting points.
• Decreases as you go down the group.

Question 4

What are the products of an alkali metal reacting with water?

Answer 4

Alkali metal + water - metal hydroxide + hydrogen

Question 5

What are the products of an alkali metal reacting with oxygen?

Answer 5

Alkali metal + oxygen –> metal oxide

Question 6

What are the products of an alkali metal reacting with chlorine?

Answer 6

Alkali metal + chlroine –> metal chloride

Question 7

What are three substances that react quickly with group 1 elements and what do they form?

Answer 7

• Chlorine (Metal chloride.)
• Oxygen (Metal oxide.)
• Water (Metal hydroxide + hydrogen)

Question 8

Why does the reactivity of group 1 metals increase as you go down the group?

Answer 8

• The outer electron is less attracted to the nucleus and easier to lose.
• Greater distance between the positive nucleus and negative electron
• The outer electron is shielded from the nucleus by internal energy levels.

Question 9

What group 1 elements float in water?

Answer 9

• Lithium
• Sodium
• Potassium
  Have low density
  Density increases as you go down the group

Question 10

What happens to the density as you down group 1?

Answer 10

Density increases

Question 11

What happens to the reactivity as you go down group 1?

Answer 11

reactivity increases

Question 12

Why does the melting point decrease as you go dow group 1?

Answer 12

• Decrease in forces of attraction between positive ion and delocalised elctrons.
• (more shells, shielding the positive nucleus.)

Question 13

Why are alkali metals stored in oil?

Answer 13

• Becuase they react with oxygen in the air rapidly.

Question 14

Why do all Group 1 elements react in the same way?

Answer 14

• All have 1 electron on outer shell.

Question 15

What happens when sodium reacts with water and a few drops of universal indicator are added?

Answer 15

• New substance formed (sodium hydroxide)
• Effervescence from Hydrogen
• Indicator green –> purple
• Sodium floats on water
• Metal gets smaller

Question 16

What happens when potassium reacts with water and a few drops of universal indicator are added?

Answer 16

• New substance formed (potassium hydroxide)
• Efferevsecene from hydrogen
• Metal gets smaller
• Ignites –> lots of energy out
• Indicator green –> purple

Question 17

What are 3 similarities in the reaction of sodium + water and potassium + water ?

Answer 17

1.) Float
3.) Fizz/effervescence
4.) Metal gets smaller