C2.1 Atomic Structure and the Periodic Table

Question 1

How did Mendeleev arrange the elements in the Periodic Table?

Answer 1

Mendeleev arranged the elements in order of increasing atomic mass
This means that elements with similar properties were lined up in his table

Question 2

How did Mendeleev use his table to predict the properties of elements that weren’t discovered?

Answer 2

He used the gaps in his table to make predictions about the properties of undiscovered elements

Question 3

Describe the structure of the atom

Answer 3

It’s a nucleus containing protons and neutrons surrounded by electrons in shells (energy levels)

Question 4

What is the size of a nucleus of an atom compared to the overall size of the atom?

Answer 4

Very Small

Question 5

What does an atom of a given element have?

Answer 5

The same number of protons in the nucleus and this number is unique to that element

Question 6

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

Answer 6

Proton - 1
Neutron - 1
Electron - 1/1840 (Negligible)

Question 7

What do atoms contain an equal number of?

Answer 7

Protons and Electrons

Question 8

What is the atomic number?

Answer 8

The number of protons in the nucleus of an atom (also known as the proton number)

Question 9

What is the mass number?

Answer 9

The total number of protons and neutrons in the nucleus of an atom (also known as the nucleon number)

Question 10

What is the Relative Atomic Mass?

Answer 10

The mean mass of an atom relative to the mass of an atom of carbon-12, which is assigned a mass of 12

Question 11

Describe the arrangement of elements in the periodic table

Answer 11

Elements are arranged in order of increasing atomic number

Horizontal rows are called periods and the atomic number increases by one from one element to the next

Vertical Columns are called groups and they contain elements with similar properties

Question 12

What does the existence of isotopes result in?

Answer 12

The existence of isotopes results in some relative atomic mass not being whole numbers

Question 13

How do you calculate the Relative Atomic Mass of an element?

Answer 13

Total Mass = (No x mass) + (No x mass)

Mass of 1 atom = Total Mass/No of atoms

Question 14

What are the rules for the filling of electron shells?

Answer 14

First Shell can contain up to 2 electrons

Second and third shell can contain up to 8 electrons

Question 15

What is the Electronic Configuration for Sodium?

Answer 15

2:8:1

Question 16

Describe the connection between the number of outer electrons and the position of an element in the Periodic Table

Answer 16

The number of occupied shells is the same as the period number

Apart from elements in Group 0 which have full outer shells, the number of electrons is the same as the group number