Groups in the periodic table

Question 1

Alkili metals

Answer 1

The elements in group 1 of the periodic table

Question 2

Physical properties of alkili metals

Answer 2

• Good conductors of heat and electricity
• Shiny when freshly cut
• Soft
• Have low melting points

Question 3

Alkali reactions with water

Answer 3

Alkali metals react with water producing an alkaline metal hydroxide and hydrogen (e.g sodium+water->sodium hydroxide+hydrogen

Question 4

Reactivity of alkali metals

Answer 4

The reactivity of the metals increases down the group:

• Li fizzes
• Na melts into a ball and fizzes rapidly
• K gives off sparks and burns purple

Question 5

Halogens

Answer 5

The elements in group 7 of the periodic table are non-metals called halogens

Question 6

Appearance of halogens

Answer 6

Fluorine (gas) pale yellow
Chlorine (gas) yellow green
Bromine (liquid) red-brown
Iodine (solid) dark grey

Question 7

Melting and boiling points of halogens

Answer 7

Going down the group:

• Melting points increase
• Boiling points increases
• Intermolecular forces between molecules become stronger (therefore more heat energy is required to overcome them)

Question 8

When simple molecular substances melt or boil:

Answer 8

• Weak intermolecular forces are overcome

- The strong covalent bonds joining atoms in each molecule do not break

Question 9

Reactivity of halogens

Answer 9

The reactivity of the elements decreases down group 7

Question 10

Halogen reactions with metals

Answer 10

Halogens react with metals to produce compounds called metal halides (e.g sodium+chlorine->sodium chloride)

Question 11

Halogen displacement reaction

Answer 11

A more reactive halogen can displace a less reactive halogen from its compounds

Question 12

OIL RIG

Answer 12

Oxidation is Loss of electrons

Reduction is Gain of electrons

Question 13

Investigating displacement

Answer 13

You can demonstrate displacement reactions by adding a halogen solution to a metal halide solution, then seeing if the mixture darkens.

Question 14

The noble gases

Answer 14

The elements in group 0 of the periodic table are known as the noble gases

Question 15

Chemical properties of noble gases

Answer 15

Noble gases are inert. this is because they have full outer shells of electrons.

Question 16

Helium

Answer 16

Use: Party balloons and airships
Properties: Low density, inert
Reason for use: Helium is less dense than air so the balloons and airships rise. It is non-flammable so does not ignite

Question 17

Argon, Krypton, Xenon

Answer 17

Use: Filling gas in filament lamps
Properties: Inert
Reason for use: The metal filament becomes hot enough to glow. The inert gases stop it burning away.

Question 18

Argon

Answer 18

Use: Shield gas during welding
Properties: Inertness
Reason for use: Argon is denser than air so it keeps air away from the metal. It is inert so the metal does not oxidize