Unit 2 Quiz 1 Review - Atomic theory & Structure

​Chemistry

Unit 2 Quiz 1 review​

History of Atomic Theory & Atomic Structure

​Democritus 460 b.c.

​Atomos - "Uncuttable"

​

​

​Robert Millikan's Oil Drop Experiment discovered the charge of the electron

• Also called the Planetary Model

• Discovered by Niels Bohr

• Describes electrons existing in different levels or Shells around the nucleus of an atom​

  • Each Level holds a different number of electrons

  • Properties depend on where electrons are​

​The Bohr Model of the atom

Multiple Choice

Used the word "atomos" to decsribe the uncuttable (indivisible) atom.

• Democritus

• Thomson

• Bohr

• Dalton

Multiple Choice

Proposed that electrons move around the nucleus in specific layers, or shells.

• Bohr

• Rutherford

• Chadwick

• Thomson

Multiple Choice

Which of the following is/are conclusions based on Rutherford’s gold foil experiment?

• Atom is mostly empty space

• The nucleus is positively charged

• The atom has a small dense nucleus

• All answers are correct

Multiple Choice

He discovered electrons

• J.J. Thomson

• John Dalton

• Ernest Rutherford

• Niels Bohr

• The dense central core of an atom

  • Contains both protons and neutrons

  • Neutrons stop protons from repelling each other

• Contains most of the mass of the atom​

  • Mass is the sum of protons and neutrons​

​

​The Nucleus

Multiple Choice

Ions are: 

• atoms with a positive or negative charge
• atoms with no charge
• atoms with ONLY a positive charge
• atoms with ONLY a negative charge

Multiple Choice

What is an ion?

• A Charged Atom
• A Large Atom
• A Small Atom
• A Cute Atom

Multiple Choice

An atom becomes _______ when it loses electrons.

• Positive
• Negative
• Neutral
• Invinsible

Multiple Choice

An atom becomes _________ when it gains electrons.

• Positive
• Negative
• Neutral
• Invinsible

Multiple Choice

What is the charge of an atom with 5 protons, 5 neutrons, and 7 electrons?

• 0

• +5

• +2

• -2

Multiple Choice

If an element contains 13 protons and 12 electrons what would be its overall charge?

• +1

• -1

• +13

• -13

Multiple Choice

A Bromine ion gains 1 electron, which of the following is the correct symbol for a Bromine ion?

• Br^-1

• Br⁺¹

• Br⁺⁷

• Br^-7

Multiple Choice

How would you write a Sulfur that has gained 2 electrons?

• S⁺²

• S^-2

• S⁺⁶

• S^-6

Multiple Choice

If an atom of Boron has 5 protons how many electrons will it need to have to be neutral?

• 3

• 4

• 5

• 6

• We distinguish between different elements based on their atomic number

  • The number of protons they have

• The Mass number is the number of neutrons + number of protons in an atom

  • Mass No. is measured in atomic mass units (amu)​

​

​Atomic number and mass number

Fill in the Blanks

How many protons are in a Carbon atom?

(Type a whole number only!)

Multiple Choice

What is the charge of a neutron, and what is its location in an atom?

• Neutral charge, located in nucleus.

• Negative charge, located in nucleus.

• Neutral charge, located in the orbitals/cloud.

• Negative charge, located in the orbitals/cloud.

Multiple Choice

What is the charge of a proton, and what is its location in an atom?

• Neutral charge, located in nucleus.

• Positive charge, located in nucleus.

• Neutral charge, located in the orbitals/cloud.

• Positive charge, located in the orbitals/cloud.

Multiple Choice

What is the charge of an electron, and what is its location in an atom?

• Negative charge, located in nucleus.

• Neutral charge, located in nucleus.

• Negative charge, located in the orbitals/cloud.

• Neutral charge, located in the orbitals/cloud.

Multiple Choice

An electron and proton are ALIKE because...

• Neither has a charge.

• Both are charged.

• Both are in the nucleus.

Multiple Choice

A neutron and proton are ALIKE because...

• Neither has a charge.

• Both are charged.

• Both are in the nucleus.

Multiple Choice

Protons are DIFFERENT from neutrons because...

• One is in the nucleus, the other is in the orbitals/cloud.

• One has a charge, the other does not.

• Both are in the nucleus.

​Now Isotopes!

​All carbon atoms have 6 protons in the nucleus, but there may be 6, 7, or 8 neutrons. These are called isotopes of carbon. There are isotopes of every element!

Isotopes, mass number

An atom's mass is its total of protons and neutrons . The electron cloud mass is small enough to ignore.

Carbon-12, carbon-13, & carbon-14 are carbon's isotopes. 12, 13, and 14 are their masses.

Multiple Choice

The mass number of an atom is the number of ...

• Electrons plus Protons

• Neutrons plus Electrons

• Protons plus Neutrons

Multiple Choice

What Greek philosopher was the first person to propose the idea that matter is made of tiny particles called atoms

• Democritus

• Dalton

• Thompson

• Rutherford

• Bohr

Fill in the Blanks

In an atom of boron-11, has a mass number of 11 how many neutrons are present?

Type a whole number!

(Use your periodic table!)

Multiple Choice

Which subatomic particle identifies an element?

• Protons

• Neutrons

• Electrons

• Protons and Neutrons

Multiple Select

Which particles have a charge?

• Protons

• Neutrons

• Electrons

Multiple Select

Which particles are found in the nucleus?

• Protons

• Neutrons

• Electrons

Multiple Select

Which particles account for almost all the mass of an atom?

• Protons

• Neutrons

• Electrons

Multiple Choice

Magnesium's atomic number is 12. This means that a magnesium atom has

• 12 protons in its nucleus

• A total of 12 protons and electrons

• 12 neutrons in its nucleus

• A total of 12 neutrons and electrons

Multiple Choice

A potassium atom has an atomic mass of 39. Its atomic number is 19. How many neutrons does the iron atom have?

• 19

• 39

• 20

• 58

Multiple Choice

Two atoms that are different isotopes of the same element have

• a different number of protons but the same number of neutrons

• the same number of protons and the same number of neutrons

• a different number of protons and a different number of neutrons

• the same number of protons but different numbers of neutrons

Ions

• charged atoms formed by an atom gaining or losing electrons

Fill in the Blanks

How many neutrons does this isotope have?

Isotope Abundance and Atomic Mass

• In nature, most elements occur as a combination of two or more isotopes

  • Each isotope has a natural percent abundance​

• The average atomic mass is the weighted average of the masses of its isotopes

  • a weighted average reflects the relative abundance of each isotope found in nature

• Calculated Atomic Mass: The more common an isotope is, the more important it is in atomic mass calculations

  • Step 1: ​multiply the mass of each isotope by its natural abundance

  • Step 2: add the products of all the weighted isotopes masses

Chem 1 | Unit 1 Lessons 2 & 3

Fill in the Blanks

Element X has two naturally occurring isotopes. One isotope has a mass of 10 amu with a relative abundance of 20%. The other isotope hasa mass of 11 amu and relative abundance of 80%. What is the average atomic mass of Element X

Atomic Mass Estimations Practice Problem 2

• Consider a hypothetical element, X, that has three isotopes. Calculate the weighted- average atomic mass of the element from the following data:

  • ​Step 1: Multiply each atomic mass by it's abundance

    • 85.32 x 0.10

    • 87.51 x 0.70

    • 88.10 x 0.20

  • Add the sum of the relative masses together

Chem 1 | Unit 1 Lessons 2 & 3

​Isotope	​Abundance	​Atomic Mass
​X-85	​10%	​85.32 amu
​X-87	​70%	​87.51 amu
​X-88	​20%	​88.10 amu

Multiple Choice

How is average atomic mass determined?

• By adding all of the protons and neutrons together.

• by summing the masses of the element's isotopes, each multiplied by its natural abundance on Earth

• By multiplying of often protons and neutrons occur and adding up the averages.

Multiple Choice

If an atom has 5 protons and 6 neutrons what is the proper name of the isotope?

• Boron-1

• Boron-11

• Carbon-11

• Carbon 11

• Boron Carbonate

Multiple Choice

How many neutrons does an atom of symbol pictured have?

• 26

• -26

• 70

Multiple Choice

What is the total number of particles in the nucleus atom of symbol pictured have?

• 22

• 70

• 48

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

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