Atomic Theory and Structure of Atoms

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Questions and Answers

What is the complete symbol for Americium-241?

Am-241 (correct)

241Am (correct)

Am241

241Am-3

How many protons are present in a lithium atom?

3 (correct)

Which of the following correctly describes a molecule?

A single atom of an element

A group of elemental symbols

A combination of two or more atoms bonded together (correct)

An ionic compound

What is the molecular formula for hydrogen gas?

H2O (A) Signup and view all the answers

What is the molecular formula for the molecule that consists of 8 sulfur atoms?

S8 (C) Signup and view all the answers

Which element has the atomic symbol 'Si'?

Silicon (C) Signup and view all the answers

To name a molecule based on its formula, you should first identify what?

The elements in the molecule (D) Signup and view all the answers

How many neutrons does a potassium atom contain?

20 (A) Signup and view all the answers

What prefix is used to indicate four atoms of an element in a molecular formula?

tetra (D) Signup and view all the answers

Which of the following is the correct name for the molecule P2S5?

Diphosphorus pentasulfide (D) Signup and view all the answers

What is the correct formula for carbon tetrachloride?

CCl4 (D) Signup and view all the answers

Which of the following names uses the correct prefix for three atoms?

trichloride (A) Signup and view all the answers

What would be the correct name for SO3?

Sulfur trioxide (A) Signup and view all the answers

What is the correct way to name the compound with the formula SF4?

Sulfur tetrafluoride (D) Signup and view all the answers

Which prefix would be used for six atoms of an element?

Hexa (B) Signup and view all the answers

What is the correct chemical formula for silicon dioxide?

SiO2 (C) Signup and view all the answers

What is known as the smallest piece of an element that maintains its identity?

Atom (A) Signup and view all the answers

What does the atomic number represent in an atom?

Number of protons (A) Signup and view all the answers

Isotopes of the same element differ in the number of which subatomic particles?

Neutrons (A) Signup and view all the answers

What is the mass number of an atom with 6 protons and 6 neutrons?

12 (B) Signup and view all the answers

What is the correct representation of a carbon atom with 6 protons and 6 neutrons?

C-12 (D) Signup and view all the answers

An atom of uranium with an atomic number of 92 and a mass number of 235 contains how many neutrons?

143 (B) Signup and view all the answers

What is the mass number of a tin atom that has 50 protons and 68 neutrons?

118 (A) Signup and view all the answers

Which of the following is an appropriate symbol for an isotope of aluminum with an atomic number of 13 and mass number of 27?

Al-27 (B) Signup and view all the answers

Study Notes

Atomic Theory

Atoms are the smallest unit of an element, maintaining its identity.
The term "atom" comes from a Greek word meaning "indivisible."
Atoms are composed of subatomic particles.

Modern Atomic Theory

All matter is composed of atoms.
Atoms of the same element are identical; atoms of different elements are different.
Atoms combine in whole-number ratios to form compounds.

The Atom

Protons: Located in the nucleus; have a positive charge (1+) and a mass of approximately 1.6 × 10^-27 kg.
Neutrons: Located in the nucleus; have no charge and a mass of approximately 1.6 × 10^-27 kg.
Electrons: Orbit the nucleus; have a negative charge (1-) and a mass of approximately 9.1 × 10^-31 kg.

Atomic Number

The number of protons in an atom's nucleus defines the atomic number.
All atoms of the same element have the same atomic number.
However, atoms of the same element can have different numbers of neutrons.

Isotopes

Atoms of the same element with different numbers of neutrons are called isotopes.
The mass number is the sum of protons and neutrons in an atom's nucleus.

Atomic Symbols

Atomic symbols use the element's symbol followed by the mass number (protons + neutrons).
Example: Carbon-12 (¹²C) represents an isotope of carbon with 6 protons and 6 neutrons.

Periodic Table of Elements

Organized by increasing atomic number.
Elements' properties are related to their position on the table.
Elements are categorized as metals, metalloids, and nonmetals.

Molecules and Chemical Nomenclature

Molecules: Two or more atoms bonded strongly, behaving as a single particle.
Molecular Formula: A written representation of the number and type of atoms in a molecule. Example: H₂ (two hydrogen atoms).
Chemical Nomenclature: Rules for naming compounds.

Rules of Chemical Nomenclature

Identify the elements in the compound.
Start with the first element's name, using prefixes (e.g., mono-, di-, tri-) for additional atoms if needed.
Name the second element, incorporating prefixes (if needed) and changing its ending to "-ide."
Combine the names. Example: carbon dioxide (CO₂)
Specific rules apply when prefixes end in "a" or "o" and the second element begins with a vowel. e.g. monoxide, pentoxide.

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Description

This quiz covers the fundamental concepts of atomic theory, including the structure of atoms, the role of subatomic particles, and the modern understanding of atomic numbers. Test your knowledge of how atoms form the building blocks of matter and the relationships between different elements.