2.5 Simple molecules and covalent bonds

Question 1

molecule

Answer 1

a group of atoms bonded together representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Question 2

covalent bonds are held together by

Answer 2

weak intermolecular forces

Question 3

Properties of covalent bonds

Answer 3

low melting and boiling point
Poor conductivity
insoluble

Question 4

Covalent bond

Answer 4

When two or more non-metal atoms bond together. The atoms need more electrons to fill their outer shell, so they share to complete

Question 5

Covalent bonds have these properties because

Answer 5

They have low melting and boiling points because of the weak intermolecular forces holding them together

Question 6

Compound

Answer 6

A substance is made of two or more elements chemically bonded.
It has a definite composition

Question 7

Mixture

Answer 7

A substance made of two or more substances physically combined.
It has variable composition

Question 8

Element

Answer 8

A substance made of only one type of atom

Question 9

Proton number/atomic number

Answer 9

Is equal to the number of protons

Question 10

Electron

Answer 10

A negatively charged subatomic particle that orbits the nucleus

Question 11

Atom structure

Answer 11

An atom contains a central nucleus containing neutrons and protons surrounded by electrons in shells

Question 12

Group number

Answer 12

Represents the number of electrons in the outer shell

Question 13

Mass number/nucleon number

Answer 13

Is equal to the total number of protons and neutrons in the nucleus of the atom

Question 14

Proton

Answer 14

a positively charged subatomic particle found in the nucleus

Question 15

Periodic number

Answer 15

Represents the number of electron shells

Question 16

How to determine the electron configuration

Answer 16

Proton number= Electron number
Electron configuration goes up first in 2 in the first shell then the rest 8 2.8.8.8.

Question 17

Neutron

Answer 17

A neutrally charged subatomic particle found in the nucleus

Question 18

Calculate the relative atomic mass

Answer 18

It is the sum of (atomic mass x relative abundance) for each Isotope dived by the sum of the relative abundance.(100)

Question 19

Isotope

Answer 19

Atoms of the same element so they have the same number of protons but with a different number of nuetrons

Question 20

Why do ionic bonds have these properties

Answer 20

They have high melting and boiling points because they are held together with strong electrostatic forces in lattice of positive and negative ions
They can conduct in liquid solutions because the ions become free to move

Question 21

Ion

Answer 21

An electrically charged particle formed when an atom either loses or gains electrons.

Question 22

Anion

Answer 22

Negatively charged ion

Question 23

Cation

Answer 23

positively charged ion

Question 24

Properties of ionic compounds

Answer 24

High boiling and melting points
Good electrical conductivity when aqueous or molten and poor when solid.

Question 25

Ionic bond

Answer 25

A force of attraction between a cation and an anion (between metals and nonmetals)

Question 26

What are the similarities between diamond, silicon and graphite

Answer 26

High melting point as a lot of energy is needed to break the strong covalent bonds

Question 27

Macromolecule

Answer 27

A giant molecule created by atoms covalently bonded to one another

Question 28

What are the properties and structure of diamond

Answer 28

Made of carbon with 4 covalent bonds Is the hardest substance on earth because of it using all of its bonds

Question 29

The properties and structure of graphite

Answer 29

Is made of carbon and each atom makes 3 bonds Used as a lubricant because the layers in the structure can slide over each other because they are only held together by weak intermolecular forces Can conduct electricity because of one delocalised electron

Question 30

The three most know macromolecules

Answer 30

Diamond Graphite Silicon

Question 31

The properties and structures of silicon

Answer 31

Made of silicon and oxygen atoms in the ratio SiO2 in the same structure as diamond High melting point

Question 32

Metallic bonding

Answer 32

There are strong electrostatic attractions between the positive metal ions (cations) and the negative delocalised electrons

Question 33

Melting and boiling points in metals

Answer 33

As the metallic lattice is held together by strong electrostatic forces of attraction, metals have high melting points and boiling points.

Question 34

Electrical conductivity in metals

Answer 34

The delocalised electrons in the metallic lattice are free to move throughout the structure and so metals are good at conducting electricity.

Question 35

Malleability and ductility of metals

Answer 35

Metals are malleable and ductile