Chapter 5 - Electrons & Bonding

Question 1

what are shells

Answer 1

• energy levels, increases as shell does
• called principal quantum number, n

Question 2

atomic orbital

Answer 2

a region around the nucleus that can hold up to two electrons with opposite spins

Question 3

s-orbitals

Answer 3

• electron cloud is within shape of sphere
• each shell contains 1 s-orbital
• greater shell no., greater the radius

Question 4

p-orbitals

Answer 4

• electron cloud within shape of dumb-bell
• 3 p-orbitals at right angles to each other
• each shell from n=2 contains 3 p-orbitals
• greater the shell, the further the p-orbital from the nucleus

Question 5

d-orbitals

Answer 5

each shell from n=3 contains 5 d-orbitals

Question 6

f-orbitals

Answer 6

each shell from n=4 contains 7 f-orbitals

Question 7

no of electrons in each shell

Answer 7

1 –> 2
2 –> 8
3 –> 18
4–> 32
(2n²)

Question 8

how do electrons fill sub-shells

Answer 8

first each shell has 1 electron, then goes back and starts filling up second electron, with opposite spins

Question 9

rule with filling up orbitals

Answer 9

fill up 4s before then 3d as at lower energy level

Question 10

how to form ions

Answer 10

• draw electron configuration and remove/add electrons
• always fill and remove electrons from 4s before 3d

Question 11

shorthand electron configuration

Answer 11

• use previous noble gas
• e.g Na is [Ne]3s¹

Question 12

chromium electron configuration

Answer 12

1s²2s²2p⁶3s²3p⁶3d⁵4s¹

Question 13

copper electron configuration

Answer 13

1s²2s²2p⁶3s²3p⁶3d¹⁰4s¹

Question 14

Ni²⁺electron configuration

Answer 14

1s²2s²2p⁶3s²3p⁶3d⁸

Question 15

Nickel electron configuration

Answer 15

1s²2s²2p⁶3s²3p⁶3d⁸4s²

Question 16

ionic bonding

Answer 16

• electrostatic attraction between positive and negative ions
• holds together cations and anions

Question 17

structure of ionic compounds

Answer 17

• giant ionic lattice

Question 18

ionic compounds properties

Answer 18

• high m.p/b.p - strong electrostatic forces of attraction between oppositely charged ions need lots of energy to be overcome
• soluble in polar solvents - polar water breaks down the lattice and surrounds each ion - depends on ionic attraction, may be too strong for water to break down lattice
• doesn’t conduct electricity when solid but does when molten/aqueous - ions are free to move around - not fixed

Question 19

covalent bonding

Answer 19

• strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms
• overlap of atomic orbitals
• localised bond - only between shared pair of electrons and the nuclei of the two bonded atoms

Question 20

double covalent bond

Answer 20

electrostatic attraction between 2 shared pair of electrons and the nuclei of bonding atoms

Question 21

triple covalent bond

Answer 21

electrostatic attraction between 3 shared pair of electrons and the nuclei of bonding atoms

Question 22

dative/coordinate bond

Answer 22

covalent bond where the shared pair of electrons has been supplied by one of the bonding atoms only

Question 23

average bond enthalpy

Answer 23

measurement of covalent bond strength, larger the value, the stronger the bond