Atoms

Question 1

atom

Answer 1

• smallest part of an element that can exist

- radius of 0.1nm and have no charge

Question 2

element

Answer 2

• contains one type of atom

- represented by a symbol

Question 3

compound

Answer 3

• two or more chemically combined elements

- only separated into elements by chemical reactions

Question 4

central nucleus

Answer 4

contains protons and neutrons

Question 5

electron shells

Answer 5

contains electrons

Question 6

protons

Answer 6

• +1 charge

- relative mass of 1

Question 7

neutron

Answer 7

• 0 charge

- relative mass of 1

Question 8

electron

Answer 8

• charge of -1

- very small relative mass

Question 9

mass number

Answer 9

the number of protons and neutrons in the nucleus

Question 10

atomic number

Answer 10

the number of protons in the atom

proton number = electron number

Question 11

isotopes

Answer 11

atoms of the same element with the same number of protons but different number of neutrons

Question 12

pre 1900 atom

Answer 12

• tiny solid spheres that could not be divided

- John Dalton said this solid sphere made up the different elements

Question 13

1897 plum pudding atom

Answer 13

• ball of positive charge with negative electrons embedded in it
• JJ Thompson’s experiments showed an atom must contain small negative charges (electrons are discovered)

Question 14

1909 nuclear model

Answer 14

• positively charge nucleus at the centre surrounded by negative electrons
• proved by alpha particle experiment

Question 15

1913 Bohr model

Answer 15

• electrons orbit the nucleus a specific distances

- Bohr proposed electrons orbited in shells

Question 16

Rutherford’s scattering experiment

Answer 16

• a beam of alpha particles are directed at thin gold foil
• most alpha particles pass through
• a few + particles were deflected
• a tiny number of particles reflected back from the nucleus