Chemistry Atomic Mass and Isotopes Quiz

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Questions and Answers

What is the atomic mass of an element?

The mass of an atom without electrons

The weighted average of all isotopes of an element (correct)

The sum of protons and electrons in an atom

The sum of protons and neutrons in an atom (correct)

How is atomic mass typically expressed in scientific measurement?

In kilograms

In atomic mass units (amu) (correct)

In grams

In molecular weight units

Why are atomic mass and atomic weight considered synonymous terms?

They both describe the mass of protons

Both refer to the mass of electrons

They are both determined by the number of neutrons alone

They are both calculated from the isotopic composition of an element (correct)

What does a weighted average in relation to atomic mass indicate?

It accounts for the percent abundance of each isotope Signup and view all the answers

Using the provided example, what is the atomic weight of hydrogen if 95% is hydrogen-1, 3% is hydrogen-2, and 2% is hydrogen-3?

1.07 amu Signup and view all the answers

What would the average atomic mass of Sodium be based on the following isotopic abundances: Sodium-23 (91%), Sodium-22 (8%), Sodium-24 (1%)?

22.93 amu Signup and view all the answers

Which statement is incorrect regarding atomic mass?

Electrons significantly affect the atomic mass calculation Signup and view all the answers

What does the atomic number of an atom represent?

The number of protons in the atom Signup and view all the answers

Why do isotopes of the same element have different mass numbers?

Isotopes have different numbers of neutrons. Signup and view all the answers

How is an isotope commonly represented in notation?

Element name followed by a hyphen and mass number Signup and view all the answers

What is true about the electrons in an atom compared to its isotopes?

They have the same number as protons in both. Signup and view all the answers

What stays constant for an element while forming isotopes?

The number of protons Signup and view all the answers

Which element has the atomic number 79?

Gold Signup and view all the answers

What is the mass number of an isotope that has 1 proton and 2 neutrons?

3 Signup and view all the answers

What does the atomic number represent for an atom?

The total number of protons Signup and view all the answers

Which statement is true regarding isotopes?

Isotopes have the same number of protons but different mass numbers. Signup and view all the answers

What is the mass number of an atom determined by?

The sum of protons and neutrons Signup and view all the answers

How can isotopes of hydrogen differ?

By having a different number of neutrons Signup and view all the answers

What is the correct hyphen notation for the isotope of carbon with 6 protons and 8 neutrons?

Carbon-14 Signup and view all the answers

What does the atomic number signify in the context of DNA comparison?

It defines the most notable characteristics of the atom. Signup and view all the answers

Which of the following elements has an atomic number equal to 6?

Carbon Signup and view all the answers

What remains constant for an element when it forms isotopes?

The number of protons Signup and view all the answers

What is the atomic mass of an element based on?

The sum of protons and neutrons Signup and view all the answers

What does the atomic mass unit (amu) represent in atomic measurements?

It is a unit that quantifies the mass of protons and neutrons. Signup and view all the answers

How is the atomic weight of an element determined?

Through a weighted average of naturally occurring isotopes Signup and view all the answers

If an element shows isotopes with 70% of Mass Number 1 and 30% of Mass Number 3, how is its atomic weight approximated?

1.7 amu Signup and view all the answers

Which of the following statements about atomic mass is true?

It reflects the average mass of isotopes taking into account their abundance. Signup and view all the answers

What is the atomic mass of Oxygen based on the provided periodic table data?

15.9994 amu Signup and view all the answers

Why is the concept of weighted averages significant in understanding atomic mass?

It allows for a more accurate representation of average mass for isotopes. Signup and view all the answers

Study Notes

Atomic Number

The atomic number of an atom represents the number of protons in the atom.
The atomic number is a defining characteristic of an element.
The atomic number is always a whole number.
The atomic number can be found on the periodic table above the element's symbol.

Isotopes

Isotopes are atoms of the same element with different numbers of neutrons.
The atomic number (number of protons) remains constant in isotopes.
The number of neutrons can vary.
Isotopes have different atomic masses.

Atomic Mass

Atomic mass is the sum of the protons and neutrons in an atom.
Atomic mass is measured in atomic mass units (amu).
Atomic mass is synonymous with atomic weight.
The atomic mass of an element is the weighted average of the masses of its naturally occurring isotopes.

How to Find Atomic Mass

The atomic mass of an element can be found on the periodic table.
The atomic mass is the decimal number within each element's box on the periodic table.
Atomic mass takes into account the abundance of each isotope of the element.

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Description

Test your knowledge on atomic mass, atomic weight, and isotopes with this quiz. Explore concepts like weighted averages and isotopic abundances through practical examples. Challenge yourself to identify correct statements about atomic structure.