Periodic Trends

Question 1

Does the atomic radius increase or decrease going across a period.

Answer 1

Decrease

Question 2

What happens to nuclear charge going across a period.

Answer 2

The number of protons and electrons increase. As opposites attract there is a stronger electrostatic attraction between the protons and electrons.

Question 3

Why is electron-electron repulsion across a period not a determining factor for atomic radius.

Answer 3

The attraction between protons and electrons outweigh.

Question 4

Does the atomic radius increase or decrease going down a group.

Answer 4

It increases

Question 5

What happens to the nuclear charge going down a group.

Answer 5

Electron numbers increase, therefore, more shells are needed. This creates more distance between the valence electrons and the atoms nucleus.

Question 6

Why does shielding increase going down a group.

Answer 6

Shielding increases as electron numbers increase down a group.

Question 7

What is shielding

Answer 7

Shielding is when inner electrons slightly block the valence electrons from being attracted to the atoms nucleus. This allows the valence electrons to stray away, therefore, increasing atomic radius.

Question 8

Do cations have a smaller or larger radius than their originating atom.

Answer 8

Smaller

Question 9

Why do Cations have a different radius compared to the atom that they originate from.

Answer 9

When the atom forms its cation its number of electrons decrease. The number of protons it hold does not change therefore the protons are pulling with the same strength on less electrons decreasing its atomic radius.

Question 10

Do anions have a smaller or larger radius than their originating atom

Answer 10

Larger

Question 11

Which of the 4 factors that determine atomic radius change when an atom forms its anion.

Answer 11

The number of electrons in the valence shell.

Question 12

What is the definition of Ionisation energy

Answer 12

The amount of energy required to remove one mole of electrons from one mole of atoms in their gaseous state

Question 13

What is the purpose of Ionisation energy of atoms in their gaseous state.

Answer 13

If Ionisation energy was calculated from an atom in its liquid or solid state the calculation would be incorrect and you would be calculating the energy used to break down the intermolecular forces also.

Question 14

What is the definition of electronegativity

Answer 14

The tendency of an atom to attract bonding electrons in a covalent bond. (How desirable electrons are to its atom)

Question 15

What is the electronegativity trend across a period and why.

Answer 15

Electronegativity increases across a period as electrons are held more tightly to its protons due to the rule of attraction.

Question 16

What is the electronegativity trend down a group on the periodic table.

Answer 16

Electronegativity decreases as electrons are further away from their nucleus due to shielding.

Question 17

What is the Ionisation trend across a period?

Answer 17

Ionisation energy should increase as the atomic radii gets smaller and electrons are more attracted to its nucleus.

Question 18

What is the exceptions to ionisation trends?

Answer 18

Orbitals that are half filled or full filled will have higher Ionisation energies.

Question 19

What is the Ionisation trend down a period?

Answer 19

Ionisation energy will decrease down a period as the atomic radii gets bigger and there is less attraction between the valence electrons and their corresponding nucleus.