Electrons, Bonding and Structure

Question 1

What is a shell?

Answer 1

A group of atomic orbitals with the same principle quantum number, n.

Question 2

What is a sub-shell?

Answer 2

A group of the same type of atomic orbitals within a shell.

Question 3

What is ionic bonding?

Answer 3

A type of bonding caused by electrostatic attraction between oppositely charged ions, in which atoms lose or gain electrons.

Question 4

What is covalent bonding?

Answer 4

A type of bonding formed when atoms share electron pairs between nuclei.

Question 5

What is metallic bonding?

Answer 5

The electrostatic attraction between positive metal ions and electrons.

Question 6

What is a giant ionic lattice?

Answer 6

A three dimensional structure of oppositely charged ions held together by strong electrostatic forces of attraction (ionic bonds).

Question 7

What is a giant covalent lattice?

Answer 7

A three dimensional structure of atoms bonded together by strong covalent bonds

Question 8

Do ionic lattices conduct electricity?

Answer 8

When melted or dissolved in water, the ions are free to move and carry charge but when solid, they do not conduct electricity.

Question 9

What is the solubility of ionic lattices?

Answer 9

They dissolve in polar solvents such as water into there respective ions.

Question 10

What is a dative covalent bond?

Answer 10

A bond formed by a shared pair of electrons that has been produced by one of the bonding atoms only.

Question 11

What are the physical properties of simple molecular structures?

Answer 11

• Low melting and boiling points
• Do not conduct electricity
• They are soluble in non-polar solvents like hexane

Question 12

What are the physical properties of giant covalent structures?

Answer 12

• High melting and boiling points

- Do not conduct electricity except graphite

Question 13

What are the five shapes of molecules in increasing order of size?

Answer 13

Linear, trigonal planar, tetrahedral, trigonal bi-pyramid, octahedral.

Question 14

What are the bond angles of each molecule shape?

Answer 14

Linear- 180°
Trigonal planar- 120°
Tetrahedral- 109.5°
Trigonal bipyramid- 90° and 120°
Octahedral- 90°

Question 15

How does a lone pair change the bond angle of a molecule?

Answer 15

Each lone pair, reduces the bond angle by about 2.5°.

Question 16

What is electronegativity?

Answer 16

A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.

Question 17

What are intermolecular forces?

Answer 17

The attractive forces between neighbouring molecules to atoms.

Question 18

What are permanent dipole-dipole interactions?

Answer 18

A weak attractive force between permanent dipoles and permanent dipoles or induced dipoles in neighbouring polar molecules.

Question 19

What are London (dispersion forces)?

Answer 19

Attractive forces between induced dipoles in neighbouring molecules.

Question 20

What are hydrogen bonds?

Answer 20

Strong permanent dipole-dipole interactions between electron-deficient hydrogen atoms and other molecules and a lone pair of electrons on a highly electronegative atom on a different molecule.

Question 21

Why is ice less dense than water?

Answer 21

When ice forms, water molecules are arranged in an orderly pattern and hydrogen bonds form between the molecules. This means ice has an open lattice and when the rigid bonds collapse, the molecules can move closer together.

Question 22

Why does water have higher than expected boiling points?

Answer 22

Hydrogen bonds are much stronger than other intermolecular forces causing it to exhibit higher melting and boiling points than other similar structures.