Atomic structure

Question 1

What does isotopic , isoelectronic and isotonic mean?

Answer 1

isotopic - same neutrons ,diff no. of neutrons
isoelectric- same no. of electrons
isotonic - same neutrons , diff no. of protons.

Question 2

What is Aufbau’s principle?

Answer 2

electrons occupy orbitals of the lowest energy first.
1s>2s>2p>3s>3p>4s>3d (arrow represents DIRECTION not strength)

Question 3

What is Pauli’s principle?

Answer 3

Each orbital can only accommodate 2 electrons in opposite spins.

Question 4

What are the two special cases for electronic configuration.

Answer 4

Cr: 1

Question 5

Why does the ionization energy generally increases across the period?

Question 6

Why is the first ionization energy of group 2 higher than group 13?

Question 7

Why is the first ionization energy of group 16 less than group 15?

Question 8

Why is there a sharp decrease in first ionization energy between each period?

Question 9

Why does ionization energy decreases down the group?

Question 10

Why does atomic radius decreases across a period?

Answer 10

• ^no. of protons , ^nuclear charge
  -electrons are added to the same electron shell hence ^ in shielding effect is negligible
  -effective nuclear charge ^
  -stronger attraction btw +ve nucleus and - valence elecctron
  -smaller atomic radius

Question 11

Why does atomic radius increase down a group?

Answer 11

-both nuclear charge and shielding effect increases hence effective nuclear increase is not significant
-principal quantum shell increase
-distance increase
-valence electron further away from nucleus
-atomic radius increases