C2: Periodic Table

Question 1

How have elements been ordered over time?

Answer 1

Elements used to be arranged in order of atomic weights (Dalton).
Law of Octaves showed that every 8th element’s properties were similar (Newlands).
Mendeleev left gaps for undiscovered elements and predicted their properties.
Elements now ordered by atomic number.

Question 2

Why are noble gases unreactive?

Answer 2

They are monatomic meaning they don’t gain or lose electrons - already have full outer shell of electrons.

Question 3

What is the equation when a metal reacts with water?

Answer 3

Metal + Water —> Metal Hydroxide + Hydrogen

Question 4

What are the characteristics of group 1 alkali metals?

Answer 4

• Reactivity increases going down the group.
• Melting and boiling points decrease going down the group.
• Low densities, some float on water.
• Soft and shiny, dull when reacts with oxygen.

Question 5

What happens when lithium reacts with oxygen, water and chlorine?

Answer 5

Oxygen: Burns with red flame, produces white solid.
Water: Fizzes steadily, gradually disappears.
Chlorine: White powder produced.

Question 6

What happens when sodium reacts with oxygen, water and chlorine?

Answer 6

Oxygen: Strong orange flame, produces white solid.
Water: Fizzes rapidly, melts into a ball and disappears quickly.
Chlorine: Burns with bright yellow flame, clouds of white powder.

Question 7

What happens when potassium reacts with oxygen, water and chlorine?

Answer 7

Oxygen: Lilac flame and white solid.
Water: Lilac flane, shiny ball, disappears very quickly.
Chlorine: Very vigorous reaction.

Question 8

What are the characteristics of group 7 halogens?

Answer 8

• Low melting/boiling points that increase going down the group.
• Poor conductors of heat/electricity.
• Exist as molecules of covalent bonds.
• More reactive halogen can displace a less reactive one.

Question 9

What does reactivity increase going down group 1 and decrease going down group 7?

Answer 9

Atomic radii and shell shieling from inner shells increase. This means that the electrostatic force of attraction between the nucleus and outer shell becomes weaker, making it easier to lose an electron but harder to gain one.

Question 10

What is reactivity?

Answer 10

The tendency for an atom to lose/gain electrons and form ions.

Question 11

What are the characteristics of transition metals?

Answer 11

• Good conductors of heat/electricity.
• Hard, strong, high densities.
• High melting/boiling points.
• Less reactive than group 1.
• Can be used as catalysts and have coloured compounds.