Chapter 2

Question 1

Matters

Answer 1

Anything that takes up space and has mass

Question 2

Elements

Answer 2

A substance that cannot be broken down to other substances by chemical reactions.

Question 3

Compound

Answer 3

A substance consisting of two or more different elements combined in a fixed ratio,

Question 4

Compounds

Answer 4

Is a substance consisting of two or more different elements combined in a fixed ratio.

Question 5

Essential elements

Answer 5

That an organism needs to live a healthy life to reproduce.

Question 6

Trace elements

Answer 6

Trace elements are required by an organism in only a minute quantities.

Question 7

Atom

Answer 7

Is the smallest unit of matter that still retains the properties of an element.

Question 8

Subatomic molecules in an atom

Answer 8

Neutron are neutral,protons are positive and electron are negatively charge.

Question 9

Atomic nucleus

Answer 9

Protons and neutrons are packed within

Question 10

Dalton

Answer 10

A unit of measurement of atomic mass is called Dalton

Question 11

Atomic number

Answer 11

Is written as a subscript to the left of symbol.. this is the number of proton in the element

Question 12

Mass number

Answer 12

Is the sum of protons plus neutrons in a nucleus of an atom.

Question 13

Atomic mass

Answer 13

Total mass of an atom which compromises proton and neutrons

Question 14

Isotopes

Answer 14

Atom have same number of proton but different neutron

Question 15

Radioactive isotopes

Answer 15

Is one which the nucleus decays spontaneously, giving off particles and energy.

Question 16

Half-life

Answer 16

The time it takes 50% of the parent isotope to decay.

Question 17

Radiometric dating

Answer 17

Is a process to measure the ratio of different isotopes and calculate how many half lives have passed since an organism was fossilised or rock was formed.

Question 18

Energy

Answer 18

Is defined as the capstone cause change

Question 19

Potential energy

Answer 19

The energy that a matter possesses because of its location or structure.

Question 20

Electron shells

Answer 20

Each shell is characterised with average distance and energy level

Question 21

Valance shell and valance electron

Answer 21

Outermost shell is known as valance shell. If incomplete the atom is reactive and if complete atom is non reactive. Outermost electron is known as valance electron.

Question 22

Orbital

Answer 22

The tree dimensional space where an electron is found 90% of the time. It has a specific shape

Question 23

Chemical bonds

Answer 23

When an atom is close enough it interacts

Question 24

Covalent bond

Answer 24

Is the sharing of a pair of valence electron by two atoms . Two or more molecules form by covalent bond is called molecules

Question 25

Single bond

Answer 25

A pair of electron shared

Question 26

Double bond

Answer 26

Two pair of electron shaker

Question 27

Bonding capacity

Answer 27

Depends on number of unbounded electron in the valance shell

Question 28

Electronegativity

Answer 28

The attraction of a particular atom for the electron of a covalent bond is called its electronegativity.

Question 29

Nonpolar covalent bond

Answer 29

The two atom in a covalent bond share electrons equally because the two have same electronegativity

Question 30

Polar covalent

Answer 30

The electron of a covalent bond are not shared equally.

Question 31

Ions

Answer 31

In a ionic bond the two atoms are unequally charge as result the more electronegative pulls the electron of less positive.The two resulting opposite charge atoms are called ions.

Question 32

Cations

Answer 32

Positively charge ion

Question 33

Anion

Answer 33

Negatively charge ion

Question 34

Ionic compound

Answer 34

Compounds that are form as a result of ionic bond

Question 35

Hydrogen bond

Answer 35

Attraction between hydrogen and an electronegative element

Question 36

Van dar Waal interaction

Answer 36

Are individually WEAK and occur only when atoms and molecules are very close together.

Question 37

Four hybrid orbital

Answer 37

- tetrahedral - angle in between is 104.5 - water is an example

Question 38

Chemical reactions

Answer 38

The making and breaking of chemical bonds, leading to change in composition of matter are called chemical reactions. Changes reactant into product.

Question 39

Reactants

Answer 39

Chemical that are mixed together

Question 40

Chemical equilibrium

Answer 40

The point at which the reaction offset one another exactly. I.e forward and reverse reaction rate is equal.