The Atom: Basic Building Block Of All Matter

Question 1

Who were six scientists who were influential to our understanding of the atom?

Answer 1

Democritus
Dalton
Thomson
Rutherford
Chadwick
Bohr

Question 2

What was Democritus’ atomic theory?

Answer 2

That matter is made up of small basic particles

Question 3

What did Dalton’s model of matter state?

Answer 3

All matter is made up of indestructible and indivisible atoms
Atoms of the same element are identical
Atoms of different elements differ from one another

Question 4

What was Dalton’s model based on?

Answer 4

The knowledge that elements combine in fixed mass ratios

Question 5

What was a shortcoming of Dalton’s model of the atom?

Answer 5

He made no reference to the electrical nature of matter

Question 6

What did Thomson discover about atoms?

Answer 6

He explored electrons

Question 7

What did Thomson discover about electrons?

Answer 7

All electrons are identical
Substances differ because of the number of electrons that they have and how they are arranged
The mass of an electron is about 2000 times less than the mass of protons

Question 8

How did Thomson think an atom looked?

Answer 8

A solid sphere with positive and negative charges evenly distributed throughout to make the atom neutral

Question 9

How Thomson research electrons?

Answer 9

He used cathode ray tubes

Question 10

What is a cathode ray tube?

Answer 10

A tube filled with gas that has a very low pressure

The glass of the tube then becomes fluorescent

Question 11

What did Rutherford discover about the atom?

Answer 11

The protons of an atom are grouped together in the nucleus
The nucleus is surrounded by “empty” space occupied by electrons
The mass of an atom is concentrated mainly in the nucleus

Question 12

How did Rutherford make his discovery?

Answer 12

He bounced alpha particles off gold foil

Question 13

What are alpha particles?

Answer 13

Positively charged particles given off by radioactive substances

Question 14

What was a shortcoming in Rutherford’s model of the atom?

Answer 14

It could not explain why electrons which move about the nucleus do not spiral inwards towards the nucleus

Question 15

What did Chadwick discover about atoms?

Answer 15

He discovered the existence of neutrons in the nucleus of an atom

Question 16

How did Chadwick discover the existence of neutrons?

Answer 16

He bombarded beryllium with alpha particles

Question 17

Why did Chadwick perform his experiment?

Answer 17

Rutherford’s model could not explain why Helium is four times heavier than Hydrogen, despite only the one difference in the number of protons

Question 18

What did Bohr contribute to atomic theory?

Answer 18

Electron can move only in fixed, permitted orbits

Therefore, this electron has a definite energy which cannot change while the electron is moving in that particular orbit

Question 19

What takes up the most space in an atom?

Answer 19

The nucleus

Question 20

What is the nucleus made out of?

Answer 20

Protons and neutrons

Question 21

What contributes the most mass to an atom?

Answer 21

The nucleus

Question 22

Where can the electrons of an atom be found?

Answer 22

In fixed orbits surrounding the nucleus

Question 23

What are the fixed orbitals of electrons called?

Answer 23

Energy levels

Question 24

In a neutral atom, what is the relationship between the number of electrons and the number of protons?

Answer 24

They are equal

Question 25

What is the atomic number of an atom?

Answer 25

The number of protons in an atom

Question 26

What does the atomic number determine?

Answer 26

The type of element that the atom is

Question 27

How do we denote the atomic number of an element?

Answer 27

By writing it as a subscript number to the bottom left of the atomic symbol of that element

Question 28

What is the mass number of atoms?

Answer 28

The mass of an atom | It is found by adding the number of protons and neutrons together

Question 29

How do you find out how many neutrons are in an atom?

Answer 29

Mass number - atomic number

Question 30

How do you denote the mass number of an element?

Answer 30

By writing it in the top left hand corner next to its chemical symbol

Question 31

What is an isotope?

Answer 31

An atom that has the same number of protons that it usually has, but a different number of neutrons i.e its mass is different

Question 32

Does an isotope behave differently chemically?

Answer 32

No

Question 33

What are the atomic masses found on the Periodic Table?

Answer 33

Average masses

Question 34

How can an atom lose or gain electrons?

Answer 34

Through a chemical reaction

Question 35

What happens when a neutral atom loses or gains electrons?

Answer 35

It becomes charged

Question 36

What is an ion?

Answer 36

A charged ion

Question 37

When does an atom become positively charged?

Answer 37

When it loses an electron | It will now have more protons than electrons

Question 38

When will an atom become negatively charged?

Answer 38

When it gains an electron | It will now have more electrons than protons

Question 39

What is a cation?

Answer 39

A positively charged ion

Question 40

What is an anion?

Answer 40

A negatively charged ion

Question 41

What symbol can be used to denote a proton?

Answer 41

Z

Question 42

What symbol can be used to denote neutrons?

Answer 42

N

Question 43

What is the formula for atomic mass?

Answer 43

Atomic Mass = Z + N

Question 44

When an electron is moving in an energy level, can it emit or absorb energy?

Answer 44

No

Question 45

When does an electron emit energy?

Answer 45

When it falls to a lower energy level

Question 46

When does an electrons absorb energy?

Answer 46

When it jumps to a higher energy level

Question 47

What does it mean to say that energy radiated or absorbed by electrons is quantised?

Answer 47

It is limited to certain energy values determined by the energy difference between the energy levels

Question 48

What does the wave model do?

Answer 48

Determines the general region or area where an atom will be found

Question 49

What is an orbital?

Answer 49

A region in space where the probability of finding an electron is greatest

Question 50

What are the two main types of orbitals?

Answer 50

S | P

Question 51

What is the shape of an s-Orbital?

Answer 51

Spherical

Question 52

How are s-Orbitals arranged?

Answer 52

Symmetrically around the nucleus | They differ in size

Question 53

How many s-Orbitals occur in each energy level?

Answer 53

One

Question 54

What is the shape of p-Orbitals?

Answer 54

They are dumbbell in shape

Question 55

How are p-Orbitals arranged?

Answer 55

In groups of three | At right angles to one another

Question 56

What are the three types of p-Orbitals called?

Answer 56

X- horizontal Y- Vertical Z- diagonal

Question 57

Where are p-Orbitals found?

Answer 57

From the second energy level onwards

Question 58

What is the Afbau principle used for?

Answer 58

To determine how electrons occupy the orbitals of an atom

Question 59

What preference do electrons have when occupying orbitals?

Answer 59

They always occupy the orbitals having the lowest possible energy values

Question 60

Which orbitals have the lowest possible energy levels?

Answer 60

The ones closest to the nucleus

Question 61

What does Pauli's Exclusion Principle say?

Answer 61

That each orbital can contain a maximum of two electrons provided they spin in opposite directions

Question 62

Why do electrons spin in opposite directions?

Answer 62

The two negatively charged particles repel one another

Question 63

What does Hund's Rule say?

Answer 63

No p-orbital will have two electrons in it until all the p-orbitals in that energy level have at least one electron

Question 64

What are core electrons?

Answer 64

Electrons found in the inner, full energy levels

Question 65

What are valence electrons?

Answer 65

The electrons in the outermost energy level

Question 66

What does an Afbau diagram look like?

Answer 66

Number of energy levels shown by a number on the y-axis Orbitals shown by blocks Electrons shown by arrows pointing in opposite directions Type of orbital shown by a letter beneath the block

Question 67

What is electron configuration?

Answer 67

A type of notation showing the position of electrons

Question 68

What does electron configuration look like?

Answer 68

Number of energy level Type of orbital Superscript number denoting the number of electrons