AS

Question 1

What does it mean when an atom is electrically neutral

Answer 1

Number of protons=Number of electrons

Question 2

What is an atomic number

Answer 2

Number of protons

Question 3

What is a nucleon number/Mass number

Answer 3

Number of protons + Number of neutrons

Question 4

How is an ion formed

Answer 4

When an atom loses/gains electron(s) and the number of electrons and protons is not equal

Question 5

What is a valence shell

Answer 5

Outermost shell of an atom

Question 6

What is the electronic configuration of an atom with 19 electrons

Answer 6

2,8,8,1

Question 7

What does the group number give information about

Answer 7

Number of valence electrons

Question 8

What does the period number give information about

Answer 8

Number of occupied electron shells

Question 9

What are isotopes

Answer 9

Isotopes are atoms of the same element with the same number of protons but different number of neutrons

Question 10

Do isotopes of the same element have the same chemical properties and why?

Answer 10

Yes. They have the same number of electrons

Question 11

Do isotopes of the same element have the same physical properties (e.g. melting properties, boiling points, density) and why?

Answer 11

They have slightly different chemical properties due to the different masses of the isotopes

Question 12

What is the sum of the relative abundance of all the isotopes for one element equal to

Answer 12

100

Question 13

What is the relative atomic mass of an atom

Answer 13

The average mass of an atom, taking into account the different natural occurring isotopes and their relative abundance

Question 14

Calculate the relative atomic mass of carbon:
12C 98.89%
13C 1.11%
14C trace

Answer 14

12.0

Question 15

Calculate the relative abundance of nCr
52Cr 83.6%
53Cr 9.50%
54Cr 2.30%
nCr ?

Hence determine the isotopic mass “n” of nCr

Answer 15

4.60%

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