Atomic Structure

Question 1

What are the 3 subatomic particles? As well as the charges, mass and position in the atom?

Answer 1

Protons - Charge +1 - Mass 1 - Nucleus
Neutrons - Charge 0 - Mass 1 - Nucleus
Electrons - Charge -1 - Mass 1/1840 - Energy Shells

Question 2

Define proton number

Answer 2

Number of protons in the nucleus, equal to the number of electrons

Question 3

Define mass number

Answer 3

Number of protons and neutrons in the nucleus

Question 4

Describe the behaviour of subatomic particles in an electric field.

Answer 4

Electrons are deflected the strongest/ pulled the most towards the positive charge.
Neutrons are not affected by either positive nor negative charge.
Protons are deflected less than electrons, but more than neutrons as they have higher mass than electrons and get pulled towards the negative charge.

Question 5

What are the 2 factors that affect what happens to the subatomic particles in an electric field?

Answer 5

Speed of the particles
Energy of the particles

Question 6

Define atomic radius

Answer 6

Half the distance between the nuclei of 2 covalently bonded atoms of the same type - only for neutral atoms
Cannot determine the atomic radius of noble gases as they are unable to covalently bond

Question 7

Define electron shielding

Answer 7

The blocking of valence shell electron attraction by the nucleus, due to the presence of inner-shell electrons
- Other electrons are shielded from the pull of the nucleus by inner-shell electrons
- Results in a weaker electrostatic attraction between the nucleus and valence electrons

Question 8

Describe the 2 trends in atomic radius.

Answer 8

Across the period:
- Increase in the number of protons
- Increase in nuclear charge and greater nuclear attraction
- Atoms within the same period experience similar shielding as they have the same number of energy shells

Down the group:
- Increase in energy shells = increase in shielding

Question 9

Define ionic radius

Answer 9

Distance of the outermost shell of electrons from the nucleus of an ion
Depends on ion formed
Rule - the more negative the ion, the bigger the ionic radius

Question 10

Define isotope

Answer 10

Atoms of the same element with the same proton number, different number of neutrons
Have the same chemical properties - same number of electrons
Have different physical properties - different mass and density

Question 11

Define relative atomic mass

Answer 11

Average mass of one atom of an element relative to the mass of one carbon-12 to which the value of 12 units is assigned - must have 1 decimal place

Question 12

Define relative isotopic mass

Answer 12

Relative mass of a single isotope compared with an isotope of carbon-12 which is assigned a relative mass of 12.0 - must be a whole number