5 Electrons And Bonding

Question 1

For the first four energy levels, state how many electrons there are in each.

Answer 1

For n=1, 2

For n=2, 8

For n=3, 18

For n=4, 32

(You can use 2n²)

Question 2

Shells are made up of ______________________, a region around the nucleus that can hold up to ___________ electrons with ____________ spin.

Answer 2

Shells are made up of atomic orbitals, a region around the nucleus that can hold up to two electrons with opposite spin.

Question 3

Name the different types of orbitals.

Answer 3

There are s, p, d, and f orbitals.

Question 4

How many electrons are in a p orbital?

Answer 4

A single p orbital, p_x, p_y, or p_z, can contain up to two electrons.

Question 5

How many f orbitals are there in the fourth energy level?

Answer 5

Seven.

Question 6

Name the element with the following electron configuration [Ne]3s¹.

Answer 6

Sodium

Question 7

Give the electron configuration of Ni and Ni²⁺.

Answer 7

Ni: 1s²2s²2p⁶3s²3p⁶3d⁸4s²

Ni²⁺: 1s²2s²2p⁶3s²3p⁶3d⁸

Question 8

Define ionic bonding.

Answer 8

Ionic bonding is the electrostatic attraction between positive and negative ions.

Question 9

^{Why do most ionic compounds have high melting and boiling points?}

Answer 9

High temperatures are needed to provide the large quantity of energy needed to overcome the strong electrostatic attraction between the ions.

Question 10

What are the two main process of dissolving an ionic compound in water?

Answer 10

The ionic lattice must be broken down;

as water molecules attract and surround the ions.

Question 11

State some of the main properties of ionic compounds.

Answer 11

High melting and boiling points.

Tend to dissolve in polar solvents such as water.

Conduct electricity in the liquid state or when aqueous.

Question 12

Predict which will have the higher solubility in water:

NaCl or MgCl₂

Answer 12

The ions are similar size, so ionic ratio is not likely a factor.

Mg²⁺ has a higher charge than Na⁺ so there will be stronger electrostatic attraction for MgCl₂.

Therefore, NaCl will me more soluble than MgCl₂.

Question 13

Define covalent bonding.

Answer 13

Covalent bonding is the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 14

What is a molecule?

Answer 14

A molecule is the smallest part of a covalent compound that can exist whilst retaining the chemical properties of the compound.

Question 15

How many covalent bonds do the following make:

Carbon

Nitrogen

Oxygen

Hydrogen

Answer 15

Carbon - 4

Nitrogen - 3

Oxygen - 2

Hydrogen - 1

Question 16

Sketch the dot and cross diagram of BF₃

Answer 16

Question 17

Explain why sulfur can form, two, four, or six

covalent bonds.

Answer 17

It has 6 outer shell electrons. Sulfur can fit up to 18 electrons in its outer shell.

These six can arrange as two lone pair with 2 singles to covalently bond; one lone pair with 4 singles to covalently bond; or no lone pairs with 6 singles to covalently bond.

Question 18

Define a dative bond.

Answer 18

A dative covalent bond, also called a coordinate bond, is a covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only.

Question 19

Br-Br has an average bond enthalpy of 193 kJ/mol.

And O-H has an average bond enthalpy of 464 kJ/mol.

Which molecule has the stronger covalent bond?

Answer 19

OH has the stronger bond.