2.1 Atoms

Question 1

Mass number

Answer 1

Mass number: the mass of protons and neutrons in an atom

Electron mass is negligable

Question 2

Atomic number

Answer 2

Atomic number: number of protons in an atom

Question 3

Hydrogen isotopes

Answer 3

Protium

Deuterium

Tritium

Question 4

Atom

Answer 4

Atom: smallest unit of an element

Question 5

Observations of the atoms:

Answer 5

1. All matter is composed of atoms
2. Atoms cannot be created nor destroyed
3. Atoms of the same element are a like in every way
4. Atoms of different elements are different
5. atoms can combine in small numbersto form molecules

Question 6

Electron

Neutron

Proton

Answer 6

Electron: a negatively charged particles

Neutron: a particle without charge

Proton: a positively charged particle

Question 7

Bohr’s model of hydrogen

Answer 7

Question 8

Cation

Anion

Answer 8

Cation: a positively charged atom which has lost an electron

Anion: a negatively charged atom which has gained an electron

Question 9

Mass spectrum

Answer 9

Mass psectrum indicates the number of isotopes, their mass and relative abundance