discoveries of atom/pt

Question 1

ernest rutherford discovered that:

Answer 1

mass is concentrated in the nucleus
the nucleus contains protons
atoms consist of mostly empty space

his model was the nuclear model

Question 2

john dalton discovered that:

Answer 2

all matter is made up of tiny particles called atoms
atoms cannot be created or destroyed
atoms cannot be broken and they are all identical

Question 3

JJ thompson discovered that:

Answer 3

negatively charged electrons are scattered through a positively charged material

this was called the plum pudding model

Question 4

explain Rutherford’s gold foil experiment

Answer 4

Rutherford beamed the Alpha particles on gold foil which was surrounded a detector.

The detector was coated with a fluorescent substance so when the alpha particles were to hit it, it would flash

Rutherford realised that the alpha particles went straight through the gold foil but some bounced back and some were deflected at large angles

Question 5

explain what Rutherford concluded from his experiment

Answer 5

the plum pudding model couldn’t be correct

1. most the particles went through the foil meaning atoms are mostly made up of empty space because
2. the nucleus has a positive charge this is because two subatomic particles which are the same would repeal against each other, leading the conclusion that as they repelled the nucleus must be positive like the alpha particle

2 the + charge and mass are concentrated in a tiny volume in the nucleus-this means the chance of being on that exact collision is small so only a few alpha particles could bounce back

Question 6

mendeleev’s periodic table:

Answer 6

noble gases aren’t given a specific place in the periodic table

the pt has gaps

ordered by atomic mass

8 groups and 12 periods

Question 7

modern periodic table:

Answer 7

noble gases are given a place in the periodic table

pt have NO gaps

ordered by atomic number

18 groups and 7 periods

transition metals ARE separated