C5 - Electrons and Bonding Flashcards Preview

Year 12 - Chemistry > C5 - Electrons and Bonding > Flashcards

Flashcards in C5 - Electrons and Bonding Deck (31):
1

What are orbitals?

Regions around the nucleus of an atom where electrons are more likely to be found at any one time.
All orbitals can hold only two electrons only.

2

What orbitals are found in the first shell?

s orbitals
Hold 2 e-

3

What orbitals are found in the second shell?

s and p orbitals
p holds 6 e-

4

What orbitals are found in the third shell?

s, p and d orbitals
d holds 10 e-

5

What orbitals are found in the fourth shell?

s, p, d and f orbitals.
f holds 14 e-

6

Where are electrons found?

They exist at fixed energy levels.
Energy levels are called principle energy levels and are given a principle quantum number (n)

They're found at orbitals.

7

What are s orbitals like?

Spheres
1s is the closest to the nucleus

Altogether it holds 2 electrons per orbital

The 4s orbital has less energy than the 3d orbital

(When removing electrons to make ions, electrons are first taken from the 4s orbital (whereas they'd be added to 3d first))

8

What are p orbitals like?

A figure of eight in 3 directions (x y z)

Each p orbital holds 6 electrons
(2x 2y 2z)

9

Hat are d orbitals like?

They come in 5 shapes

(2 electrons at end of each type of shape)
They hold 10 electrons altogether

The 3d orbital has more energy than the 4s orbital

(When removing electrons to make ions, electrons are first taken from the 4s orbital (whereas they'd be added to 3d first))

10

What are f orbitals like?

They come in 7 shapes

(2 electrons at end of each type of shape)
They hold 14 electrons altogether

11

What is Hund's rule?

Hund's rule states that single electrons occupy all empty orbitals within a sub-level before they start to form pairs in orbitals.
(This rule is broken with chromium and copper)

12

Why do ionic compounds have high melting and boiling points?

Because there are very strong ionic bonds and strong electrostatic forces which require a lot of energy to break.

It is a lattice structure with bonds in all directions so there are many ionic bonds.

13

What are melting and boiling points affected by?

Charge - strengths of attraction

Size of the ions - a smaller ion means the electrons are closer to the nucleus so there are stronger forces and more energy therefore more energy is needed to overcome these bonds

14

What's electron spin?

A property of electrons represented by arrows in a box.
Two electrons in an orbital must have opposite spins which help to counteract the repulsion between the negative charged of the two electrons.

15

What's the order which orbitals are filled?

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p,

5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, (8s, 5g, 6f, 7d, 8p, and 9s)

16

What's ionic bonding?

The electrostatic attraction between oppositely charged (positive and negative) ions.
It holds together cations (positive) and anions (negative) in ionic compounds.
This produces a giant ionic lattice

17

What is the solubility of ionic compounds?

Many ionic compounds dissolve in polar solvents e.g. water.
The slight charges of the polar water molecules break down the lattice and surround each ion in solution.

In a compound made of ions with large charges, the ionic attraction may be too strong or water to break down the lattice structure. This type of compound wouldn't be very soluble.

18

What affects the solubility of ionic compounds?

The relative strengths of the electrostatic attraction within the ionic lattice and between the ions and water molecules.
(As charge increases, solubility decreases)

19

What is the conductivity of ionic compounds?

Ionic lattices cannot conduct electricity when solid as the ions aren't free to move.
When molten or dissolved however, the ions are free to move carrying charge so conduction can occur.

20

What are lone pairs?

Pairs of electrons which aren't shared with another atom.

21

What is covalent bonding?

The electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms.

(The overlap of atomic orbitals occuring between non-metallic elements)

It is very different to ionic bonding as it is very localised, acting solely between the shared pair of electrons and the nuclei of the bonded atoms, producing a molecule.

22

What is the expansion of the octet?

The fact that atoms can result in having more (or less) than 8 electrons in its outer shell.
A case where an atom shares more than eight electrons with its bonding partners.

The octet rule can be 'expanded' by some elements by utilizing the d-orbitals found in the third principal energy level and beyond. Sulfur, phosphorus, silicon, and chlorine are common examples of elements that form an expanded octet.
E.g. SF6

23

What's another name for dative covalent bonding?

Coordinate bonding

24

What is dative covalent bonding?

A co-ordinate bond (also called a dative covalent bond) is a covalent bond (a shared pair of electrons) in which both electrons come from the same atom. (rather than one from each).

A lone pair is needed for dative covalent bonding - the lone pair on the atom donates its electrons into the vacant orbital on the hydrogen.

25

What is average bond enthalpy?

Bond energy.
The larger the bond enthalpy, the stronger bond.

26

What is the max number of electrons in the first four shells?

Shell 1: 2
Shell 2: 8
Shell 3: 18
Shell 4: 32

As of shell 3, compounds are able to use the 'expansion of the octect' rule.

27

What is the electron configuration of sodium (full and short hand)
Na 11

Full:
1s2 2s2 sp6 3s1

Short:
[Ne] 3s1

28

What is the electron configuration of fluorine:
F9

1s2 2s2 2p5

29

What is the electron configuration of krypton:
Z = 36

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6

30

What does each symbol mean in 1s2?

1 is the shell
s is the sub shell
2 is the number of electrons

31

What are double and triple covalent bonds?

The electrostatic attraction between two or three shared pairs of electrons and the nuclei of the bonding atoms.