Atomic Structure, Relative Mass & Conservation of Mass

Question 1

What is an atom made of? Give the charges and relative mass of these. (3)

Answer 1

1. Electron: -1 charge, 0.0005
2. Proton: +1 charge, 1
3. Neutron: 0 charge, 1

Question 2

How do you calculate the relative atomic mass (A r) of an element? (1)

Answer 2

( (Relative atomic mass of 1 isotope x abundance percentage) + (Relative atomic mass of another isotope x abundance percentage) ) divided by 100.

Question 3

How do we calculate the number of particles in a substance?

Answer 3

Number of particles = Avagadro’s constant x No. of moles

Question 4

What is Avagadro’s constant? What does it represent? (2)

Answer 4

1. 6.022 x 10²³

2. Number of particles in a mole

Question 5

What is the Law of Conservation?

Answer 5

No atoms are lost or made in a chemical reaction.