Atomic Structure

Question 1

What is the electronic configuration of Sulfur-32 which has a proton number of 16.

Answer 1

2,8,6

Question 2

What is the electronic configuration of hydrogen-1 with a proton number of 1.

Answer 2

1

Question 3

What is the electronic configuration of helium-4 with a proton number of 2.

Answer 3

2 in the first shell

4 is the mass number, since it is neutral it will have 2 electrons to equal the number of protons (+2) + (-2) = 0

Question 4

What is the electronic configuration of sodium-23 with a proton number of 11.

Answer 4

2,8,1

Check your answer:

Na is is group 1 and should have 1 outer electron

Question 5

What is the electronic configuration of chlorine-35 with a proton number of 17?

Answer 5

2,8,7

Check:

Chlorine is in group 7 and should have 7 outer electrons

Chlorine is in period 3 and should have 3 electron shells

Question 6

What is the electronic configuration of oxygen-16 with a proton number of 8?

Answer 6

2,6

Check:

oxygen is in group 6 and should have 6 outer electrons

oxygen is in period 2 and should have 2 electron shells

Question 7

What is the electronic configuration of Ca ²⁺

Calcium has a proton number of 20.

Answer 7

2,8,8

Ca is 2,8,8,2 but Ca ²⁺ has lost its two outer electrons to gain a full outer shell.

Question 8

What is the electronic configuration of F ^1-

Fluroine has a proton number of 9.

Answer 8

2,8

Fluorine is 2,7 but has gained one electron to make F ^1-

Question 9

What is the electronic configuration of N^3-

Nirogen has a proton number of 7.

Answer 9

2,8

Nitrogen is 2,5 but it has gained 3 electrons to give N ^3-

Question 10

What subatomic particles are found in the nucleus?

Answer 10

protons and neutrons

Question 11

What is the charge of a proton, neutron and electron respectively?

Answer 11

proton 1+, neutron 0, electron 1-

Question 12

What is the relative mass of a proton, neutrons and electron?

Answer 12

proton 1, neutron 1 - same relative mass

electron (0 or 1/1840)- more of less zero

Question 13

Name the subatomic particles which are also nucleons.

Answer 13

proton and neutrons because they are found in the nucleus

Question 14

What is an isotope?

Answer 14

An atom of the same element with same number of protons and different number of neutrons

Question 15

What is the mass number of an atom?

Answer 15

mass number = number of protons + number of neutrons

Question 16

How do you find the number of neutrons found in Na-23 which has a proton number of 11.

Answer 16

mass number - proton number = number of neutrons 23 - 11 = 12 neutrons

Question 17

How do the chemical properties of isotopes compare?

Answer 17

Isotopes have similar chemical properties because they have the same number of outer electrons.

C-12 and C-14 both have 6 protons and 6 electrons but C-14 has 2 more neutrons and is therefore slightly heavier. But they both have 4 outer electrons and behave the same chemically

Question 18

What does the group number in the periodic table represents?

Answer 18

The number of outer electrons

Question 19

What does the period number represent in the periodic table?

Answer 19

The number of electron shells

Question 20

Why is group 0 or the noble gases inert (unreactive)?

Answer 20

They have a full outer shell

Question 21

What is the octet rule?

Answer 21

Atoms gain or lose electrons to obtain a full outer shell which makes the atom more stable.

Question 22

Define relative atomic mass (RAM)

Answer 22

The average mass number of an atom relative to 1/12th the mass of Carbon-12 taking into consideration the abundance of all its isotopes.

Question 23

Naturally occurring chlorine consists of atoms of relative masses 35 (75%) and 37 (25%). Without calculating which RAM is more likely and why? 37.5, 35.5. or 36.0

Answer 23

35.5 because the number is closest to 35 which has a greater abundance of 75%.

Question 24

What is the mass number of Lithium-7 which has 3 protons?

Answer 24

7

Question 25

![]() How many neutrons does lithium-7 have? Lithium has 3 protons

Answer 25

7-3 = 4 neutrons

Question 26

![]() Which element has 10 neutrons? F-19 proton number 9 Ne-20 proton number 10 B-10 proton number 5

Answer 26

Fluorine 19 - 9 = 10 neutrons

Question 27

![]() Which element has 8 **outer** electrons? Ne-10 proton number 8 OR O-16 proton number 8

Answer 27

Neon - its electronic configuration is 2,8 Neon has 10 electrons but 8 outer electrons

Question 28

![]() Which element will form an ion with charge 3- Nitrogen found in group 3 Aluminium with 3 outer electrons sodium found in period 3

Answer 28

Nitrogen, its electronic configuration is 2,5 so it gains 3 electrons to become 2,8 with a charge of 3-

Question 29

![]() To which group and period does this element belong? Chlorine-35 Chlorine has a proton number of 17

Answer 29

The proton number is 17 therefore it has 17 electrons. The electronic configuration is 2,8,7 group 7 - it has 7 outer electrons period 3 - it has 3 electron shells

Question 30

![]() Which charge ion will this element form? Chlorine with electronic configuration 2,8,7

Answer 30

It has 7 outer electrons- it will gain one electron and will have the charge 1-

Question 31

How is a negative ion formed?

Answer 31

A neutral atom gains electrons

Question 32

How is a positive ion formed?

Answer 32

The neutral atom must lose electrons.

Question 33

What is the electronic configuration of potassium-39 with a proton number of 19? How would this change when its ion is formed?

Answer 33

2,8,8,1 it would become 2,8,8 having lost its outer electron to gain a full outer shell and become more stable

Question 34

Which ions can have the electronic configuration 2,8

Answer 34

F ^1- and Na ¹⁺ Fluorine is 2,7 but gains one to become 2,8 with a charge of 1- sodium is 2,8,1 but loses one electron to become 2,8 with a charge of 1+

Question 35

Which two ions have an electronic configuration of 2,8,8?

Answer 35

Cl ^1- and K ¹⁺ ## Footnote Chlorine is 2,8,7 and gains one electron to become 2,8,8 and gains a charge of 1- Potassium is 2,8,8,1 and losed one electron to become 2,8,8 and gains a charge of 1+

Question 36

These are the same element, they have the same number of protons but have different number of neutrons. What are they?

Answer 36

They are isotopes