THE PERIODIC TABLE

Question 1

What is the atomic number?

Answer 1

This tells you the number of protons in an atom. It is unique to each events and is the SMALLER of the two numbers given.

Question 2

What does the proton number equal?

Answer 2

Proton number = electron number

Question 3

How do you work out the number of neutrons?

Answer 3

Mass number- atomic number

Question 4

What is the mass number?

Answer 4

This is the mass of the whole atom. It is the sum of protons and neutrons.

Question 5

What is an isotope?

Answer 5

An element with the same Atomic number but different number of neutrons.

Question 6

How did Mendeleev order the elements?

Answer 6

Atomic number

Question 7

Why did Mendeleev leave gaps in the table?

Answer 7

For undiscovered elements

Question 8

What elements didn’t fit into Mendeleev’s pattern?

Answer 8

Arron and Potassium because this would mean that Potassium would be with the unreactive metals and Argon would be in a group with extremely reactive metals.

Question 9

Who had the first ideas of the periodic table?

Answer 9

John Dalton - he arranged them in order of their atomic weights which were measured in chemical reactions.

Question 10

Who had the second idea of the periodic table?

Answer 10

John Newlands.

Question 11

What was the first idea of the periodic table?

Answer 11

John Dalton - 1808 he published his table of elements in order of their atomic weights.

Question 12

What was the second idea about the periodic table?

Answer 12

John Newlands - law of octaves. The events were arranged in order of their atomic mass’. He realised that every eighth element was similar. However, his table only worked for the known elements up to calcium.

Question 13

Mendeleev’s periodic table is the one we use today. How is it different?

Answer 13

He left gaps for elements which had not been discovered yet.
To begin he ordered hem in order of their atomic weights. However, this resulted in argon (a noble gas) being in the same group as sodium (reactive metals). It would also put potassium in a group with noble gases. He simply changed their order where necessary.
However, in the 20th century they were put in order of their proton number (their atomic number).

Question 14

What resulted in elements having oddly heavy weights?

Answer 14

Isotopes.

Question 15

What are group 1 metals called?

Answer 15

The alkali metals.

Question 16

What are the properties of alkali metals?

Answer 16

Very reactive
Reactivity increases as you go down the group
Very low densities
Soft
Silvery/shiny
Melting point decreases as you go down the group.

Question 17

What are group 7 metals called?

Answer 17

The halogens.

Question 18

What are the properties of the halogens?

Answer 18

Toxic non-metals with coloured vapours.
Their melting point and boiling point decrease as you go down the group.
Poor conductors of heat and electricity.
Exist as diatomic molecules.
The elements get less reactive as you go down the group.

Question 19

What are the physical properties of the transition elements?

Answer 19

Good conductors of electricity and thermal energy.
They are hard and strong.
They have high densities.
They have high melting points.

Question 20

What are the chemical properties of the transition elements?

Answer 20

Much less reactive than group one metals. They do not react as readily with oxygen, chlorine, or water as the alkali metals do.