Atomic structure

Question 1

What is an atom

Answer 1

Smallest particles of an element that consists of electrons surrounding a nucleus, contains protons and neutrons

Question 2

What is a molecule

Answer 2

group of 2+ atoms chemically joined together

Question 3

Structure of an atom - positions

Answer 3

Atom consists of nucleus composed of protons and neutrons
Electrons orbits in shells
Atoms are neutral - electrons = protons

Question 4

Atom - relative masses, relative charges of sub-atomic particles

Answer 4

Proton
relative mass - 1
charge - +1

Neutron
relative mass - 1
charge - 0 (neutral)

Electron
relative mass - negligible (almost nothing)
charge - -1

Question 5

What is atomic number?

Answer 5

The number of protons in an atom

Question 6

What is mass number?

Answer 6

Number of protons and neutrons in an atom

Question 7

What is relative atomic mass (Ar)?

Answer 7

Average mass of an atom

Question 8

What are isotopes?

Answer 8

Atoms of the same element (same no. if protons) but different number of neutrons

Question 9

How do you calculate relative amtomic mass of an element from

Answer 9

1. Multiply % of the isotope by its mass (for both)
2. add together these answers
3. divide the answer by 100