Moles and Atoms

Question 1

Avogadros number

Answer 1

6.02 x 10^23

Question 2

How many protons, neutrons and electrons does hydrogen have?

Answer 2

P - 1
E - 1
N - 0

Question 3

The relative molecular mass of Hydrogen is? Why?

Answer 3

1. Because it has one proton and no neutrons

Question 4

Mass of an electron relative to a proton

Answer 4

~ 2000x less

Question 5

What is a standard solution?

Answer 5

A solution that has a known concentration of all parts

Question 6

What makes an idea primary standard?

Answer 6

1. be pure
2. be stable (not oxide in the air or absorb oxygen)
3. not absorb moisture from the air
4. have a relatively large molecular mass

Question 7

Examples of primary standards:

Answer 7

Potassium hydrogen phthalate (KHP) (standardises aqueous alkalis)
sodium carbonate (standardizes aqueous acids)

Question 8

What is a volumetric flask?

Answer 8

Glassware that is accurately calibrated to calculate volume

Question 9

1ml is ? cm^3?

Answer 9

1 cm^3

Question 10

Atomic number is:

Answer 10

Number of protons in the nucleus (Z)

Question 11

Atomic mass number is…

Answer 11

Number of protons and electrons of an element. (A)

Question 12

Isotopes have the same…

Answer 12

1. Number of protons
2. Number of electrons
3. Atomic Number
4. Chemical properties

Question 13

Isotopes have different…

Answer 13

1. Number of neutrons
2. mass number
3. physical properties

Question 14

What is an isotope

Answer 14

Atoms of the same element (same number of protons/atomic number) with a different number of neutrons (different mass number)

Question 15

Relative isotopic mass

Answer 15

The mass of one atom of an isotope relative to 1/12th of the mass of carbon-12.
Because they are relative values, they don’t have numbers

Question 16

Relative atomic mass

Answer 16

The mass of one atom of an element relative to 1/12th of carbon-12

Question 17

Define Ionisation Energy

Answer 17

The energy required to remove one electron from each atom of one mole of gaseous atoms to form one mole of gaseous +1 ions. Normally given in kj/mol.

Question 18

Ionisation energy of lithium…

Answer 18

519kj/mol

Question 19

If the ionization energy is positive the reaction is endothermic or exothermic?

Answer 19

Endothermic

Question 20

An endothermic reaction is one which…

Answer 20

has a positive ionization energy. i.e. the energy is provided

Question 21

What four factors effect ionization energy?

Answer 21

1. Charge on the nucleus
2. Atomic radius
3. Electron shielding
4. Electron configuration

Question 22

Equation for the gradient of the line

Answer 22

y = mx + c

Question 23

How to work out y in the equ^n y = mx + c

Answer 23

The value of Y when x = o

Question 24

How to work out the gradient of the line

Answer 24

Choose two separate points on the line, note down their coordinates. Draw a triangle from both points using the slop of the line as the hypotenuse. Work out the change along the x-axis and the change along the y-axis, then do ∆y/∆x.

Question 25

Energy levels

Answer 25

Atomic energy levels are the energies of electrons
in atoms. Quantum theory tells us that each
electron has a definite energy. When atoms gain or
lose energy the electrons may jump from one
energy level to another.

Question 26

Group (periodic table)

Answer 26

A group is a vertical column of elements in the
periodic table. Elements in the same group have
similar properties because they have the same
outer electron configuration.

Question 27

Mass to charge

ratio

Answer 27

The mass to charge ratio, m/z, is the ratio of the
relative mass, m, of an ion to its charge, z.
Spectrometers usually operate so that z is normally
1.

Question 28

Period (periodic table)

Answer 28

A period is a horizontal row of elements in the

periodic table.

Question 29

Relative formula mass

Answer 29

The relative formula mass of a compound is the
sum of the relative atomic masses of all the atoms
in its formula.

Question 30

Define Shielding

Answer 30

This is the effect of the inner electrons which
reduces the pull of the nucleus on the electrons in
the outer shell of an atom. Because of the shielding
the electrons in the outer shell are attracted by an
‘effective nuclear charge’ which is less than the full
charge on the nucleus.

Question 31

Extrapolation

Answer 31

Extrapolation of a graph extends the line beyond

the experimental range of values.

Question 32

Independent variable

Answer 32

The one condition that is changed in the experiment

Question 33

Ordinary form

Answer 33

This is a number written with no powers of ten

included.

Question 34

Proportion

Answer 34

Proportion is the ratio of a part compared to the

whole amount.

Question 35

Standard form

Answer 35

This writes a number in two parts multiplied
together. The first part is a number greater than 1
and less than 10, the second part is the number 10
raised to a power which is a whole number.

Question 36

Theoretical yield

Answer 36

A theoretical yield is the mass of product obtained

if the reaction goes according to the equation.

Question 37

Variable

Answer 37

A variable in an experiment is an item, factor or
condition that can be controlled, changed or
measured.

Question 38

Weighted mean

Answer 38

A weighted mean is an arithmetic mean of a set of
numbers in which some of the numbers carry more
significance than others.

Question 39

Shell n = 1 holds how many electrons?

Answer 39

2

Question 40

Shell n = 2 holds how many electrons?

Answer 40

8

Question 41

Shell n = 3 holds how many electrons?

Answer 41

18

Question 42

Shell n = 4 holds how many electrons?

Answer 42

32

Question 43

Names of sub-shells

Answer 43

s, p, d, f

Question 44

Sub-shells are divided into

Answer 44

Atomic orbitals

Question 45

Atomic orbitals are defined by…

Answer 45

1. Energy leve;
2. Shape
3. Direction in space

Question 46

What shape is formed by the s orbital?

Answer 46

Sphere/circle

Question 47

What shape is formed by the p orbitals?

Answer 47

Figure of 8