Atomic Structure

Question 1

How has Dalton’s model of the atom changed over time?

Answer 1

• Atoms are hard round spheres that cannot be broken down into simpler parts - today we know atoms contain protons, neutrons and electrons
• Atoms of an element are all identical - today we know atoms of an element maybe isotopes with different numbers of neutrons

Question 2

The relative charge/mass of : protons

Answer 2

+1

1

Question 3

The relative charge/mass of : neutrons

Answer 3

0

1

Question 4

The relative charge/mass of : electrons

Answer 4

-1

1/1836

Question 5

Atomic number

Answer 5

The number of protons in the nucleus

Question 6

Mass number

Answer 6

The number of protons + the number of neutrons

Question 7

Do atoms of different elements have the same atomic number?

Answer 7

Yes, all atoms of an element have the same number of protons, this is what makes it an atom of that element

Question 8

Why do atoms contain equal numbers of protons and electrons?

Answer 8

All atoms have no charge because the number of positive protons is equal to, and cancels out the number of negative electrons

Question 9

What is an isotope of an element?

Answer 9

Atoms with the same number of protons but a different number of neutrons

Question 10

Why do some elements have a relative atomic mass that is not a whole number?

Answer 10

These elements have isotopes, so relative atomic mass = the average mass of an atom of an element compared to 1/12 of a ¹²C atom. Taking into account the isotopes and their abundance

Question 11

Abndance

Answer 11

(RAM) Ar = ∑(mass x abundance) / total abundance