Periodic table

Question 1

How did Mendeleev order the periodic table?

Answer 1

• Increasing atomic weight
• Which meant that there were gaps for undiscovered elements
• Showed elements with similar chemical properties lined up in groups

Question 2

Why was Mendeleev’s periodic table accepted

Answer 2

predicted the properties of an element (gallium) which he left a gap for

Question 3

What is an isotope?

Answer 3

An element with the same amount of protons and electrons but a different amount of Neutrons

Question 4

How to calculate relative atomic mass of isotopes?

Answer 4

1) multiply atomic mass by the abundance
2) add the values from step one together
3) divide values from step two by total abundance

Question 5

Properties of metals

Answer 5

• Solid at room temp
• High melting point
• Good conductors
• Shiny
• Hard and strong
• Form basic oxides
• Positive ions formed
• Malleable and ductile

Question 6

Properties of non-metals

Answer 6

• solid, liquid and gas at room temp
• Low melting points
• Insulators except carbon
• Dull
• Brittle
• Form acidic oxides
• Form negative ions

Question 7

Why do the group 1 elements get more reactive as you go down the group?

Answer 7

• Atom itself is bigger
• Outer shell electrons further away from the nucleus
• Attraction between outer shell electrons and nucleus is weaker
• electron can be lost more easily therefore element more reactive

Question 8

Why do the boiling point of the noble gases increase as you go down?

Answer 8

• The mass increases as the atoms get bigger

Question 9

Properties of the group 1 elements

Answer 9

• Lower melting points in comparison to other metals
• Low density
• High reactivity
• Soft
• Good conductors

Question 10

Properties of the group 0 elements

Answer 10

• Unreactive

- Low boiling point

Question 11

Reaction of lithium in water

Answer 11

• React with the oxygen to create a layer of oxide

- Floats on the water and gives off hydrogen gas

Question 12

Reaction of sodium with water

Answer 12

• Reacts more quickly than lithium with oxygen
• Floats on water and gives off hydrogen gas more vigorously
• Melts into a ball

Question 13

Reaction of potassium with water

Answer 13

• Reacts more quickly than sodium with oxygen

- Hydrogen gas reacts with the heat and catches fire

Question 14

Why does the reactivity of the halogens decrease as you go down the group

Answer 14

• Atoms get bigger as they go down the group
• Smaller the atoms the greater the forces of attraction between the nucleus and outer shell electrons
• When they gain electron(s) in reaction, attraction between gained electron is weaker because of the size of the atom.