Abundance of Elements

Isotopes, Ions and Average Atomic Mass

By TROB

Ion Notation

• Same as isotope

• includes charge in upper right

• + means LESS ELECTRONS than PROTONS

• (-) means MORE ELECTRONS than PROTONS

Ions

• Ion means charged atom

• To be charged it needs more or less electrons than protons

• more electrons = NEGATIVE

• less electrons = POSITIVE

ISOTOPES:

• Same Element

• Different Mass Number

• WHICH MEANS DIFFERENT # of NEUTRONS

Average Atomic Mass

• DIFFERENT than Mass Number

• Average of all of the isotopes of an atom found in nature.

How to tell which isotope is more abundant?

• CLOSEST TO ROUNDED AVERAGE ATOMIC MASS

• So the most abundant isotope of Gold would be?

• Gold - 197

Multiple Choice

Adding or subtracting neutrons (charge = 0, mass = 1) makes the element change into an...

• ion
• mixture
• isotope
• neutral atom

Multiple Choice

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

Multiple Choice

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
How many protons does this element have?

• 32
• 33
• 34
• no way to know

Multiple Choice

Calcium has three different isotopes. One has a mass of 35.00 amu; another has a mass of 41.00 amu; and another has a mass of 40.00 amu. Which isotope is the most abundant of the three?

• 40.00 amu
• 41.00 amu
• 35.00 amu
• impossible to tell

Multiple Choice

An element has three different isotopes. One has a mass of 35.00 amu; another has a mass of 36.00  amu; and another has a mass of 38.00  amu. What is the average atomic mass of this element?

• 36.33 amu
• 37.00 amu
• 12.11 amu
• impossible to tell

Multiple Choice

4.35% of all X atoms have a mass of 39.946 amu. 83.79% have a mass of 41.941 amu, 9.50% have a mass of 42.941 amu, and 2.36% have a mass of 43.939 amu. What is the average atomic mass of atom X?

• 41.97 amu
• 42.19 amu
• 10.43 amu
• 40.04 amu

Multiple Choice

An isotope has three forms.  30% have a mass of 4 amu, 20% have a mass of 5 amu and 50% have a mass of 3 amu.  Average atomic mass will be closest to

• 2 amu
• 3 amu
• 4 amu
• 5 amu

Multiple Choice

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 9.012, Beryllium
• 12.011, Carbon
• 6.941, Lithium
• 10.812, Boron

Multiple Choice

How many electrons?

• 9

• 4

• 5

• 2

Multiple Choice

How many neutrons?

• 9

• 4

• 5

• 2

Multiple Choice

The atomic number is equal to _.

• the number of protons and electrons
• the number of neutrons only
• the total number of protons and neutrons
• the number of protons neutrons and electrons

How they get that number

• % abundance of that isotope x actual mass of that isotope

• add together

• divide by 100 (if you didn't put into percentage first)

Multiple Choice

What is the charge on a lithium atom that looses 1 electron?

• +1
• 0
• -1
• -2

Multiple Choice

Is the element shown in this image an ion, isotope or normal atom?

• atom
• isotope
• cation (+ ion)
• anion (- ion)

Multiple Choice

How many protons does this isotope of titanium have? Hint titanium has an atomic number of 22.

• 48
• 22
• 26
• 70

Multiple Choice

What element is this?  What is the mass number of this atom?

• sodium, 23
• magnesium, 23
• magnesium, 12
• sodium, 11

Multiple Choice

Which atom has  4 neutrons?

• Li-6
• Li-7
• Li-8
• they have the same # of neutrons

Multiple Choice

What is the atomic number of Fe? (click to see image)

• 26
• 55.845
• 56
• None of these

Multiple Choice

How many neutrons does B (Boron) contain?

• 5
• 11
• 6
• 10.811

Multiple Choice

Carbon has an atomic number of 6 and an atomic mass of 12. Which elements are considered isotopes of carbon?

• Carbon-12
• Carbon-13
• Carbon-14
• Both Carbon-13 and Carbon-14

Multiple Choice

How many neutrons does Lithium have (atomic mass = 6.94)

• 3
• 4
• 6.94
• 24.94

Multiple Choice

An atom with the same number of protons and electrons (no charge) and the expected atomic mass or number of neutrons from the periodic table.

• Neutral/Normal Atom

• Ion

• Isotope

Multiple Choice

An atom that has gained or lost electrons in an attempt to become stable/bond with another atom.

• Normal/Neutral Atom

• Ion

• Isotope

Multiple Choice

A negatively charged ion that has gained electrons to satisfy the octet rule (metals do this)

• Anion

• Cation

• Neutral Atom

• Isotope

Multiple Choice

A positively charged ion that has lost electrons to satisfy the octet rule (non-metals do this)

• Anion

• Cation

• Neutral Atom

• Isotope

Multiple Choice

Atoms of the same element that have different mass than expected because they have a different number of neutrons.

• Neutral Atom

• Ion

• Isotope

• Cation

Multiple Choice

If an atom has 9 protons and 10 electrons it has a charge of ____.

• 0

• -1

• +1

• -2

Multiple Choice

If an atom has 4 protons and 2 electrons it has a charge of ____.

• 0

• -2

• +2

• +1

Multiple Choice

If an atom has a charge of +3 and an atomic number of 5 it should have _______ electrons.

• 1

• 2

• 3

• 4

Multiple Choice

If an atom has a charge of -2 and an atomic number of 16 it should have _______ electrons.

• 14

• 16

• 18

• 20

Multiple Choice

If an atom has a charge of 0 (neutral) and an atomic number of 8 it should have ____ electrons.

• 0

• 8

• 7

• 9