The periodic table: Classification of elements

Question 1

Periodicity

Answer 1

The regular repetition of properties of the elements arising from patterns in their electron configuration.

Question 2

Metalloids

Answer 2

Silicon (Si), Germanium (Ge), Arsenic (As), Antimony(Sb), Tellurium (Te), Polonium (Po).

Question 3

Atomic radius (Increases down a group)

Answer 3

The number of occupied electron levels increases. (Distance ^)

Question 4

Atomic radius (Decreases across a period)

Answer 4

The attraction between the nucleus and the outer electrons increases as the nuclear charge increases. (Distance decreases)

Question 5

Ionic radius (Increases down a group)

Answer 5

No. of electron energy levels increases (Distance ^)

Question 6

Ionic (Decrease across a period)

Answer 6

Increase in nuclear charge across the Pd. The increased attraction between the nucleus & electrons pulls the outer energy level closer to the nucleus. (Distance decreases)

Question 7

Ionic radius eqn

Answer 7

Losing
Na→Na++e-
Gaining
Cl+e- -> Cl-

Question 8

Ionization energy (Decreases down a group)

Answer 8

Increase in electron energy levels. Greater distance weakens attraction. (Between e & n)

Question 9

Ionization energy (Increases across a period)

Answer 9

The increased effective nuclear charge between the outer electrons & the nucleus makes the electrons more difficult to remove.

Question 10

Ionization energy eqn

Answer 10

Mg>Mg+ + e-

Question 11

Electron affinity (Decreases down a grp)

Answer 11

Down a group, larger atoms and increased shielding reduce the effective nuclear charge, weakening the nucleus’s pull on added electrons, so less energy is released.

Question 12

Electron affinity (Increases across a period)

Answer 12

Nuclear charge increases while shielding stays the same, raising effective nuclear charge. Atoms strongly attract electrons, releasing more energy.

Question 13

Electron affinity eqn

Answer 13

O(g)+e- >O(g)

Question 14

Electronegativity (Decreases down a grp)

Answer 14

The bonding of electrons is furthest from the nucleus so there is reduced attraction.

Question 15

Electronegativity (Decreases down a grp)

Answer 15

The bonding of electrons is furthest from the nucleus so there is reduced attraction.

Question 16

Electronegativity (Increases across a period)

Answer 16

An increase in nuclear charge leads to increased attraction between the nucleus and the bond electrons

Question 17

Electronegativity Eqn

Answer 17

HCl>δ-H−Clδ+