GCSE Topic 1a - Atomic structure and history of the periodic table

Question 1

Columns of the periodic table are called…

Answer 1

Groups

Question 2

Rows of the periodic table are called…

Answer 2

Periods

Question 3

Name for group 1 elements

Answer 3

Alkali metals

Question 4

Name for group 2 elements

Answer 4

Alkaline earth metals

Question 5

Name for group 6 elements

Answer 5

Chalcogens

Question 6

Name for group 7 elements

Answer 6

Halogens

Question 7

Name for group 8 elements

Answer 7

Noble gases

Question 8

The group number of an element provides what information about an atom in terms of electronic structure?

Answer 8

Number of electrons in the outer shell

Question 9

The period number of an element provides what information about an atom in terms of electronic structure?

Answer 9

The number of electron shells

Question 10

All elements same the group have similar chemical reactivity. Explain why.

Answer 10

They have the same number of electrons in the outer shell.

Question 11

Explain why an atom is neutral

Answer 11

The number of protons and electrons are equal

Question 12

Define an ion

Answer 12

An atom that has lost or gained electrons

Question 13

Define a cation

Answer 13

A positively charged ion

Question 14

Define an anion

Answer 14

A negatively charged ion

Question 15

Relative mass and charge of a neutron

Answer 15

Mass: 1

Charge: 0

Question 16

Relative mass and charge of a proton

Answer 16

Mass: 1

Charge: 1+

Question 17

Relative mass and charge of an electron

Answer 17

Mass: 1/1850 OR 1/2000

Charge: 1-

Question 18

Define an isotope

Answer 18

Different atoms of an element with the same number of protons and different number of neutrons.

OR

Different atoms of an element with the same atomic number and different mass number.

Question 19

Define the term ‘relative atomic mass’

Answer 19

The weighted mean mass of atoms of an element compared to 1/12th the mass of an atom of carbon-12.

Question 20

Explain why isotopes of an element have identical chemcial properties

Answer 20

They all have the same number of electrons in the outer shell

Question 21

Explain why there are no bromine atoms with a mass of 80, but the atomic mass is 80

Answer 21

• The atomic mass is an average of different isotopes
• 50% of bromine atoms have a mass of 79
• 50% of bromine atoms have a mass of 81

Question 22

Explain why the atomic mass of chlorine is 35.5 but there are no atoms with this mass

Answer 22

• The atomic mass is an average of different isotopes
• 75% of chlorine atoms have a mass of 35
• 25% of chlorine atoms have a mass of 37

Question 23

Formula for calculating the relative atomic mass of chlorine

Answer 23

• (25/100 x 37) + (75/100 x 35) = 35.5
• 35 and 37 are the masses of the two isotopes of chlorine.
• 25/100 is 25% and is the percentage of the chlorine-37 isotope
• 75/100 is 75% and is the percentage of the chlorine-35 isotope

Question 24

Formula for calculating the relative atomic mass of bromine

Answer 24

• (50/100 x 79) + (50/100 x 81) = 80
• 79 and 81 are the masses of the two isotopes of chlorine.
• 50/100 is 50% and is the percentage of the bromine-79 isotope
• 50/100 is 50% and is the percentage of the bromine-81 isotope

Question 25

Electronic conguration of a lithium **atom**

Answer 25

2 , 1

Question 26

Electronic conguration of a lithium **1+ ion**

Answer 26

2

Question 27

Electronic conguration of a fluorine **atom**

Answer 27

2 , 7

Question 28

Electronic conguration of a fluorine **1- ion**

Answer 28

2 , 8

Question 29

Which element in period 2 has an **atom** with the electronic configuration **2,8**?

Answer 29

Neon

Question 30

Which element in period 2 has an **ion** with an electronic configuration of **2,8** and a charge of **1-**?

Answer 30

Fluorine The ion is F^-

Question 31

Which element in period 2 has an **ion** with an electronic configuration of **2,8** and a charge of **2-**?

Answer 31

Oxygen The ion is O^2-

Question 32

How many protons are there in the nucleus of a lithium atom?

Answer 32

Three

Question 33

How many neutrons are there in the nucleus of a lithium atom?

Answer 33

Four

Question 34

How many electrons are there in a lithium atom?

Answer 34

Three

Question 35

How many electrons are there in the first shell of a lithium atom?

Answer 35

Two

Question 36

How many electrons are there in the outer shell of a lithium atom?

Answer 36

One

Question 37

How many electrons are there in the outer shell of a lithium ion?

Answer 37

Zero

Question 38

Russian scientist who designed the modern periodic table

Answer 38

Dmitri Mendeleev Note that the periodic table was not discovered. The elements were discovered.

Question 39

Number of elements known to Dmitri Mendeleev

Answer 39

63

Question 40

English polymath who designed a precursor to the modern periodic table

Answer 40

John Newlands

Question 41

Law of Octaves

Answer 41

* The principle behind the arrangement of elements in John Newlands periodic table * There were no gaps * Every eighth element has the same properties as the first element.

Question 42

Structure of Dmitri Mendeleev's periodic table

Answer 42

* Most elements were arranged in order of increasing atomic mass. * Each group of elements had similar chemical properties and a trend in physical properties. * Gaps were left for new elements to be discovered. * Some elements were not put in order of atomic mass, such as tellurium and iodine. This is because iodine has similar chemical properties to bromine in group 7, but tellurium does not.

Question 43

Comparison of Mendeleev's periodic table and the modern periodic table

Answer 43

* For the modern periodic table elements are arranged in order of increasing atomic number. * Mendeleev could not put elements in order of increasing atomic number as protons were not discovered until later. * Mendeleev left gaps for new elements to be discovered. * The elements in the modern periodic table fit into the gaps that Mendeleev left and have chemical and physical properties similar to what he predicted. * Mendeleev's periodic table did not include the noble gases as these were not yet discovered. * Mendeleev's periodic table did not have a section for the transition metals.