Bonding, structure and properties

Question 1

What are molecules usually made from?

Answer 1

non-metal atoms

Question 2

When does a covalent molecular bond form?

Answer 2

When two non-metal atoms share their unpaired outer (valence) electrons by overlapping their electron clouds a covalent bond forms. The attraction of the two positive nuclei for the pair of shared electrons holds the atoms together. If there are a limited number of atoms in the structure it is known as a covalent molecule.

Question 3

When does a covalent bond occur?

Answer 3

When two or more non-metal atoms share their unpaired outer electrons (valence).

Question 3

What is a diatomic molecule

Answer 3

a molecule that contains only two atoms

Question 4

What are the diatomic elements?

Answer 4

I2 H2 N2 Br2 O2 Cl2 F2

Question 5

Draw and label the shapes used to draw a chemical showing its 3 dimensional figure

Answer 5

A triangle should represent A bong coming out of the page (towards you)
A dotted line should represent a bond going into the page (away from you)
A straight line should represent a bong in the same place as the page

Question 6

What are the covalent network elements and compounds?

Answer 6

Carbon silicon Boron Silicon dioxide Silicon carbide

Question 7

What is the attraction between charged particles called?

Answer 7

Electrostatic attraction

Question 8

What are ionic bonds?

Answer 8

Ionic bonds are the electrostatic forces of attraction between positive ions and negative ions

Question 9

When does ionic bonding occur?

Answer 9

Occurs when a metal atom transfers its unpaired outer electrons to a non-metal atom and this forms a positive metal Ion and a negative non-metal ion. The ions attract each other in all directions and a giant ionic lattice forms

Question 10

Describe the structure of ionic compounds

Answer 10

they have what is known as lattice structure, this is a regular arrangement of positive and negative ions

Question 11

When does a covalent network bond form?

Answer 11

When tow non-metal atoms share their unpaired outer (valence) electrons by overlapping their electron clouds a covalent bond forms. The attraction of the two positive nuclei for the pair of shared electrons holds the atoms together. If there are an unlimited number of atoms in the structure it is known as a covalent network.

Question 12

What is the melting point of a covalent network?

Answer 12

they have very high melting points, as strong covalent bonds are being broken

Question 13

Do covalent networks conduct electricity?

Answer 13

They do not conduct in any state, except graphite which has delocalised electrons

Question 14

When are covalent networks soluble?

Answer 14

they are insoluble in any solvent

Question 15

What are the five main covalent networks?

Answer 15

carbon

silicon

boron

silicon dioxide

silicon carbide

Question 16

how many atoms are in a covalent network?

Answer 16

unlimited number of atoms in the network

Question 17

Describe the melting points of ionic lattices?

Answer 17

they have high melitng points as strong ionic bonds are being broken

all ionic lattices are solid at room temperature

Question 18

When do ionic lattices conduct eletcticity?

Answer 18

not in solids

yes as melts or solutions as their ions are then free to move

Question 19

When are ionic lattices soluble?

Answer 19

tend to be soluble in water reather than non-aqueaous solvents but can vary

Question 20

How many atoms are in covalent molecular?

Answer 20

fixed number of atoms in their molecules

Question 21

when do covalent molecular molecules conduct electricity?

Answer 21

low as weak forces of attraction being broken

Question 22

Describe the melting points of covalent molecular molecules

Answer 22

not in any state

Question 23

When are covalent moleculear molecules soluble

Answer 23

tend to be more in non aqueous solvents than water but this can vary

Question 24

Describe a tetrahedral shape such as methane

Answer 24

four hydrogen atoms symmetrically arranged around a central carbon atom, forming 109.5° bond angles.

Question 25

Describe a trigonal pyrimidial shape

Answer 25

It has three bonded atoms and one lone pair on the central atom which creates a three-sided pyramid with bond angles of about 107°

Question 26

Describe an angular shape

Answer 26

when a central atom has two bonded atoms and two lone pairs. The bond angle is about 104.5°, and the lone pairs push the bonded atoms closer together, creating a bent shape.

Question 27

Describe a linear shape

Answer 27

a central atom bonded to two atoms with bond angles of 180°. The atoms are arranged in a straight line, with no lone pairs on the central atom