1 Atoms, Periodic table, History of Atom, Isotopes

Question 1

What are isotopes

Answer 1

Atoms with same number of protons and electrons but different number of neutrons

Question 2

What is the ar equation

Answer 2

(Atomic mass x abundance)+(Atomic mass x Abundance)/100

Question 3

What are four difference between the plum pudding model and nuclear model

Answer 3

Mass
Charge
Electrons
Empty space

Question 4

Which particle was discovered first

Answer 4

Electrons

Question 5

Give 2 reasons why gallium helped prove Mendeleevs table was right

Answer 5

1 It proved that Mendeleevs table was right as he predicted that there would be something in Group 3
2 His periodic law stated that properties depended on the atomic weight and he was right.

Question 6

Why did Mendeleev reverse the order of some elements

Answer 6

This is so that elements fit in with the chemical trends and properties

Question 7

Key difference between alkalis and transition metals

Answer 7

Transition metals form mulitple oxides/catalysts/coloured compunds/strong/good conductors
Alkalis are soft/ dull outside shiny interior/react with water to make alkali solution with hydroxide

Question 8

What change did Niels Bohr make to the nuclear model

Answer 8

Electrons have fixed energy levels but can move between them by absorbing or emitting energy.
He added the shells and nucleus.

Question 9

Radius of atom and nucleus in m

Answer 9

Atom=1x10^-10
Nucleus=1x10^-14

Question 10

In the periodic table what is the top and bottom number on an element

Answer 10

The mass is the top and atomic number is bottom

Question 11

What is a compound and mixture

Answer 11

Both formed from two or more elements though compounds are chemically combined whilst mixtures are not.