C1 - Atomic Structure

Question 1

What is an Atom?

Answer 1

An atom is a tiny particle of which all substances are made from.

Question 2

What is an Element?

Answer 2

An element is a substance made up of only one type of atom.

118 elements
92 naturally occurring
26 man-made

Question 3

What is the name of the table where all the elements are arranged?

Answer 3

The Periodic Table

Question 4

What is a compound?

Answer 4

A substance made up of 2 or more types of atoms, that have chemically bonded.

Question 5

Who first described atoms as solid spheres?

Answer 5

John Dalton

Question 7

What are the 3 main developments of the structure of an atom?

Answer 7

1. JJ Thompson’s Plum Pudding Model
2. Rutherford’s Nuclear model of the atom
3. Bohr’s model of the atom

Question 8

What is the Plum Pudding Model?

Answer 8

A sphere of positive charge with electrons embedded in it.

Question 9

What is Rutherford’s nuclear model of the atom?

Answer 9

A dense positively charged nucleus with electrons orbiting around it.

Rutherford also added empty space.

Question 10

After Bohr’s model of the atom, who discovered that there are neutrons in the nucleus?

Answer 10

James Chadwick

Question 11

What are the 3 components of an atom?

Answer 11

Protons (+) (nucleus)
Electrons (-) (outside nucleus)
Neutrons (0) (nucleus)

Question 12

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

Answer 12

Protons = 1
Neutrons = 1
Electrons = Almost 0

Question 13

Why are atoms always neutral?

Answer 13

Because the number of protons is always equal to the number of electrons.

Question 14

What is an Ion?

Answer 14

An Ion is a charged atom or group of atoms.

Question 15

What is an Isotope?

Answer 15

Isotopes are atoms of the same element with different numbers of neutrons.

E.g there are 3 Hydrogen Isotopes

Hydrogen - 1 neutron - 1 proton - 1 electron
Deuterium - 2 neutrons - 1 proton - 1 electron
Tritium - 3 neutrons - 1 proton - 1 electron

Question 16

Which physical property differs in pure samples of different isotopes of the same element?

Answer 16

Density - the density of the nucleus varies due to the different number of neutrons.

Chemical properties, caused by the electronic structures of atoms, remain the SAME.

Question 17

Why are Elements in Group 1 and 7 the most reactive?

Answer 17

Because they need to either gain or lose 1 electron to become electronically stable as an Ion.

Question 18

What is Bohr’s model of the atom?

Answer 18

A dense nucleus with electrons arranged in fixed energy levels. This is the current model.

Question 19

What do electrons orbit the nucleus in?

Answer 19

Electronic shells

Question 20

How many electrons can the first shell contain?

Answer 20

2 electrons

Question 21

How many electrons can the second and third shell contain?

Answer 21

8 electrons

Question 22

How many electrons can the fourth and above shell contain?

Answer 22

8 electrons

Question 23

What is the electronic arrangement of Oxygen?

Answer 23

2.6

8 electrons in oxygen as the atomic (proton) number is 8.

Maximum of 2 electron in the first shell so the second shell has 6 electrons. 2 + 6 = 8

Question 24

What does the reactivity of an element depend on?

Answer 24

The number of electrons in the outermost shell - the group number.

Group 1 have 1 electron in the outer shell and Group 2 have 2 electrons in the outer shell. The trend continues.