Atomic structure and Isotopes 2.1.1

Question 1

What does the atomic number (little number) tell you?

Answer 1

The number of protons in the atom

Question 2

What does the Mass number (big number) tell you ?

Answer 2

Number of protons plus number of Neutrons

Question 3

How do you know the number of electrons?

Answer 3

Its the same as the number of protons unless it’s an ion.

Question 4

How are the number of electrons affected when there is an ionic charge?

Answer 4

If has lost an electron to become positively charged the electron number will less.

If it has gained an electron to become negatively charges the electron number will be higher.

Question 5

What are the charges on the subatomic particles?

Answer 5

Proton: +1
Neutron: 0 Neutral
Electron: -1

Question 6

What particles are sometime known as nuclides or nucleons

Answer 6

Collective term protons & neutrons

Question 7

What is the definition of an Isotope?

Answer 7

Atoms of the same element that have the same number of protons but different number of neutrons so therefore different masses.

Question 8

What is the definition of Relative Atomic Mass?

Answer 8

The weighted mean mass of an atom of an element compared with 1/12th the mass of an atom of Carbon - 12

Question 9

How do you work out Relative atomic mass?

Answer 9

Multiply the mass number by the percentage abundance of each isotope add them together and divide by 100.

MAKE SURE ITS TO ONE DECIMAL PLACE!!!!! EVEN IF ITS ZERO AFTER IT.

Question 10

What is the definition of Relative isotopic mass?

Answer 10

The mass of an atom of an isotope compared with 1/12th the mass of an atom of carbon - 12

(Eg. The relative isotopic mass 25cl is 35.0
This means 35x heavier than 1/12th of an atom of carbon 12)

Question 11

How do you work out Relative molecular mass / Relative Formula mass ?

Answer 11

Simply ass the relative masses of the constituent atoms
i.e. c2 H6 ( 2x 12.0) + (6 x 1.0) = 30.0

The relative mass of a compound is the same.