Atomic Structure

Question 1

Electron shell

Answer 1

Energy level within an atom that may be occupied by a fixed number of electrons

Question 2

Subshell

Answer 2

Subdivision of an electron shell, containing a fixed number of orbitals at same energy level

Question 3

Orbital

Answer 3

A region of space in which up to 2 electrons may be located

Question 4

S subshell

Answer 4

2 electrons, one orbital

Question 5

P subshell

Answer 5

6 electrons, 3 orbitals

Question 6

D subshell

Answer 6

10 electrons, 5 orbitals

Question 7

F subshell

Answer 7

14 electrons, 7 orbitals

Question 8

The aufbau principle

Answer 8

It states that subshells are filled in order from lowest to hughest energy, and a lower-energy subshell will be completely filled before electrons move to a higher-energy subshell

Question 9

Pauli exclusion principle

Answer 9

It states that only a maximum of two electrins mat be gound in an atomic orbital, and that if an orbital is filled the electrons will have opposite spin

Question 10

Hunds rule

Answer 10

It states that electrons in a partially filled subshell will arrange themselces so as to form the maximum number of half filled orbitals (bc repulsion)

Question 11

Order of subshell filling

Answer 11

1s,2s,2p,3s,3p,4s,3p etc

Question 12

Radius size across the period (l to r)

Answer 12

Decreases bc more nuclear pull

Question 13

Radius size down the group ( top to bottom)

Answer 13

Increases bc more energy levels

Question 14

Core charge across the period (l to r)

Answer 14

Increases bc mire valence electrons tf less inner electrons

Question 15

Core charge down the group ( top to bottom )

Answer 15

Remains constant

Question 16

Electronegativity across the period (l to r)

Answer 16

Increases bc:

• number of occupied energy levels stays constant and atomuc radius decreases (bc increasing core charge)
• nuclear charge increases but number of inner shell electrons stay the same (shielding constant) so core charge increases
• tf valence mire strongly attracted ^ electroneg

Question 17

Electronegativity down the group

Answer 17

Decreases bc:

• number of occupied energy levels increases, tf atomic radius increases
• nuclear charge increases, hw electron shielding (no of inner shell electrons) also increases so core chage remains same
• tf, further down, outermost electron is farther from nucl AND the more electrons an atom has bw outermost and nucl. Tf less attraction to nucl

Question 18

Checklist for same period comparison (eg K and Br)

Answer 18

• shell no and atomic radius
• core charge and shielding
• radius and higher core charge and valence electrons = nuclear pull
  THREE SENTENCES

Question 19

Checklist for same group (eg Ca and Be)

Answer 19

• no of energy levels and atomic radius
• same core charge diff nuclear charge bc same inner shells BUT diff electron shielding
• larger atomic radius and equivalent core charge = valence of larger being more weakly attracted OR smaller has stronger pull
  THREE SENTENCES

Question 20

Ionisation energy trend down a group

Answer 20

Decreases

Question 21

Ionisation energy across a period

Answer 21

Increasing bc bigger core charge

Question 22

shape affects

Answer 22

melting point, boiling point, hardness and solubility

Question 23

NO LONE PAIRS:

• 2 bonding pairs
• 3 bonding pairs
• 4 bonding pairs

Answer 23

linear, trigonal planar, tetrahedral

Question 24

0,1,2 LONE PAIRS

Answer 24

tetrahedral, trigonal pyramidal, v-shaped/bent