Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pure Chemistry (Sec 3) > Chapter 03 - Atomic Structure > Flashcards

Chapter 03 - Atomic Structure Flashcards

1
Q

What are atoms?

A

Atoms are the smallest particle of an element that can still have chemical characteristics of an element

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 sub atomic particles in an atom?

A

Protons and neutrons in the nucleus and electrons moving around the nucleus in the electron shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the relative mass of a proton?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the relative mass of a electron?

A

1/1840

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the relative mass of a neutron?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the relative charge of a proton?

A

+1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the relative charge of a electron?

A

-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relative charge of a neutron?

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is an atom electrically neutral?

A

1) An atom has equal number of positively charged protons and negatively charged electrons.
2) The positive and negative charges cancel each other out.
3) Thus, an atom is electrically neutral and has no net charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which 2 subatomic particles make up the mass of the atom?

A

Protons and neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In an atom the proton number is also the ____ ____

A

Atomic number - shows number of protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In an atom the mass number is also the ____ ____

A

Nucleon number - shows number of protons and neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Number of protons = ?
(in an atom)

A

Number of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Number of neutrons = ?
(in an atom)

A

Nucleon number - proton number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Element V
Nucleon number = 51
Proton number = 23
How many protons, electrons and neutrons are present in element V?

A

Proton = 23
Electron = 23
Neutrons = 28

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a electronic configuration?

A

The arrangement of electrons in an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where do the electrons have the most and least amount of energy?

A

Electrons in the inner electron shell has the lowest energy while electrons in the outer shell has the highest energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the maximum electrons allowed in the first 3 electron shells?

A

First shell: 2
Second shell: 8
Third shell: 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the valence shell?

A

The electron shell furthest from the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the electrons in a valence shell called?

A

Valence electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How can you use valence electrons to determine whether an element is a metal or non metal? (For the first 20 elements only)

A

The valence electrons of the first 3 elements (1,2,3) shows that the element is a metal
The valence electrons of the 4th to 20th element (4,5,6,7..) shows that the element is a non metal

22
Q

When is an atom unreactive?

A

When the atom has a maximum number of electrons in the valence shell, it becomes stable and unreactive

23
Q

What are the 2 characteristics of noble gases?

A

Inert and exists as monatomic elements

24
Q

What are is the name of the group of elements in the periodic table that are stable?

A

Noble gases

25
Q

Which atom has a duplet electronic configuration?

A

An atom with a maximum of 2 electrons in only the first electron shell, Helium

26
Q

When does an atom have an octet electronic configuration?

A

An atom with a maximum of 8 electrons in the second or third electron shell, e.g Neon

27
Q

How are elements in the periodic table arranged?

A

Elements are arranged in increasing proton number

28
Q

What are isotopes?

A

Isotopes are atoms of the same element that have the same proton number but different neutron number, resulting in different nucleon number

29
Q

Isotopes are expressed using their ____ ____

A

Nucleon number (e.g chlorine-35, chlorine-37)

30
Q

What are the 2 similarities of isotopes?

A

1) Same number of protons and electrons
2) Similar chemical properties

31
Q

What are the 2 differences in isotopes

A

1) Different mass number (due to neutron number)
2) different physical properties

32
Q

What does the group number represent in a periodic table?

A

Number of valence electrons

33
Q

What does the period number represent in a periodic table?

A

Number of valence shells

34
Q

How are ions formed?

A

When an atom loses or gains electrons and the proton number is not equal to the electron number. This causes the atom to not be electrically neutral forming an ion

35
Q

What is an ion?

A

An ion is a charged particle formed when an atom loses or gains electrons

36
Q

What are the 2 types of ions?

A

Cations and anions

37
Q

When do cations (+) and anions (-) form?

A

Cation: When an atom loses electrons
Anion: When an atom gains an electron

38
Q

What do most atoms not have and seek for it?

A

Atoms do not have a stable electronic configuration (because their valence shell is not completely filled) and seek a noble gas configuration

39
Q

In order to achieve a noble gas configuration, what do atoms do?

A

Atoms lose or gain electrons so that their valence shells will have the maximum amount of electrons

40
Q

Usually do metals for cations?

A

Yes, metals often lose electrons to form cations while non metals gain electrons to form anions

41
Q

What is the subatomic particle responsible for the chemical properties of an atom?

A

Electrons

42
Q

What subatomic particles do not change when atom forms an ions?

A

Proton and neutron number

43
Q

When a sodium atom becomes a sodium ion, how does it change in positive, negative and net charge and electronic configuration?

A

Sodium atom:
Positive charge: 11+
Negative charge: 11-
Net charge: 0
Electronic configuration: 2,8,1
Sodium ion:
Positive charge: 11+
Negative charge: 10-
Net charge: 1+
Electronic configuration: 2,8

44
Q

When a fluorine atom becomes a fluoride ion, how does it change in positive, negative and net charge and electronic configuration?

A

Fluorine atom:
Positive charge: 9+
Negative charge: 9-
Net charge: 0
Electronic configuration: 2,7
Fluoride ion:
Positive charge: 9+
Negative charge: 10-
Net charge: 1-
Electronic configuration: 2,8

45
Q

What is valency?

A

Valency refers to the number of valence electrons of an atom involved in gaining, losing or sharing
(E.g. atom gains/loses/shares 2 electrons, valency is 2)

46
Q

What can valency help us find?

A

Chemical formula of a substance
e.g. Mg atoms lose 2 electrons to form Mg ions so the valency is 2
Cl atom gains 1 electron to form Cl ions so the valency is 1
When Mg and Cl combine, the chemical formula of magnesium chloride is found by exchanging their respective valency
MgCl2

47
Q

What is relative abundance?

A

Relative abundance refers to the percentage of an isotope of an element compared to the total number of isotopes of the element

48
Q

Element X has two isotopes:
Isotope X-90 → Mass = 90, Abundance = 25%
Isotope X-92 → Mass = 92
Abundance = 75%
What is the Relative Atomic Mass (Ar) of element X?

A

1) Convert percentages
25% = 0.25
75% = 0.75
2) Multiply
90 x 0.25 = 22.5
92 x 0.75 = 69.0
3) Add together
22.5 + 69.0 = 91.5
Since 25% and 75% = 100%, Ar = 91.5

49
Q

Element Y has two isotopes:
Isotope Y-16 → Mass = 16
Isotope Y-18 → Mass = 18
The Relative Atomic Mass (Ar) of element Y is 17.2.
Find the relative abundances of the two isotopes.

A

1) Let 𝑥 be relative abundance
Let the relative abundance of Y-16 = 𝑥
Since the relative abundance of the isotopes add up 100%, the relative abundance of Y-18 will = 100 - 𝑥
2) Substitute into formula
17.2 = [ (16 x 𝑥) + (18 x (100-𝑥)) ] / 100
𝑥 = 40
3) Final values
Relative abundance for
Y-16 = 40%
Y-18 = 60%

50
Q

Isotope Z-10 → Mass = 10, Abundance = 10%
Isotope Z-11 → Mass = 11, Abundance = 20%
Isotope Z-12 → Mass = 12, Abundance = 20%
Find the Ar of Z

A

1) Convert percentages into decimals
10% = 0.1
20% = 0.2
20% = 0.2
2) Multiply isotopes mass by abundance
10 x 0.1 = 1
11 x 0.2 = 2.2
12 x 0.2 = 2.4
3) Add them
1 + 2.2 + 2.4 = 5.6
Since 10% + 20% + 20% = 50% and not 100%, divide the total relative abundance as a decimal:
Ar = sum of mass x abundance / total abundance
50% = 0.5
5.6/0.50 = 11.2
Ar = 11.2

51
Q

Element T has two isotopes:
Isotope T-25 → Mass = 25
Isotope T-27 → Mass = 27
The Relative Atomic Mass (Ar) of element T is 25.6.
1. Find the relative abundances of T-25 and T-27.
2. What is the percentage difference between the two abundances?

A
  1. 1) Let relative abundance of T-25 = 𝑥
    Let relative abundance of T-27 = 100 - 𝑥
    2) Substitute into formula
    25.6 = [ (25 x 𝑥) + (27 x (100-𝑥) ] / 100
    𝑥 = 70
    3) Final values
    Relative abundance for
    T-25 = 70%
    T-27 = 30%
  2. 1) Find the difference in percentages
    70% - 30% = 40%
    2) Take the difference divided by the larger percentage abundance and times 100
    (40/70) x 100

Pure Chemistry (Sec 3) (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions