electrons and bonding

Question 1

atomic orbitals

Answer 1

region around the nucleus that can hold up to 2 electrons, with opposite spin

Question 2

shells

Answer 2

• regarded as energy levels
  -energy increases as shell number increases
  -contain orbitals

Question 3

principal quantum number, n

Answer 3

shell number or energy level number

Question 4

s orbitals

Answer 4

each shell from n=1 contains one s orbital
- spherical shape
- the greater the shell number, n, the greater the radius of the orbital

Question 5

p orbitals

Answer 5

• dumb-bell shape
  -each shell from n=2 contains three p orbitals
• the greater the shell number, n, the further the p-orbital is from the nucleus

Question 6

d and f orbitals

Answer 6

• each shell from n=3 contains five d- orbitals
  -each shell from n=4 contains 7 f orbitals

Question 7

number of electrons in each shell

Answer 7

shell number of electrons
1 2
2 8
3 18
4 32

Question 8

filling of orbitals

Answer 8

• increasing energy: the 3d subshell is at a higher energy level than the 4s subshell so the 4s subshell is filled first
• opposite spin: counteracts repulsion
• filled singly first: prevents any repulsion between electrons until there are no further orbitals available

Question 9

electron configuration

Answer 9

shows how subshells are occupied by electrons
eg Kr:
1s2s2p3s3p4s3d4p
often add subscripts for number of electrons within each subshell

Question 10

shorthand electron configuration

Answer 10

expressed more simply in ter3ms of previous noble gases plus the outer electron subshells

Question 11

blocks and the periodic table

Answer 11

-s-block highest energy electrons in the s-subshell (left block of 2 groups)
-p-block highest energy electrons in p subshell (right block of 6 groups)
- d-block highest energy electrons in the d-sub- shell (centre block of 10 groups)

Question 12

ions of d block elements

Answer 12

the energy of the 4s and 3d subshells are very close together so , once filled, the 3d energy level falls bellow the 4s energy level
The 4s subshell fills before 3d subshell
but 4s subshell also empties before 3d subshell