Chemistry Chapter 2 Quiz

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Questions and Answers

What is the goal of atomic interactions?

To form chemical compounds

To achieve stability by completing their valence shells (correct)

To share or transfer valence electrons

To create hydrogen bonds

Which type of chemical bond is the strongest in aqueous environments?

Hydrogen bonds

Van der Waals interactions

Covalent bonds (correct)

Ionic bonds

Which of these statements is NOT true about covalent bonds?

They involve the sharing of valence electrons between two atoms

They are the weakest type of chemical bond (correct)

They can create molecules when two atoms are held together

They can be single or double bonds depending on the number of shared electrons

What is the difference between a molecular formula and a Lewis dot structure?

Molecular formula shows the arrangement of atoms and bonds, while Lewis dot structure shows the valence electrons around each atom (B) Signup and view all the answers

What is the valence of an atom?

The number of electrons required to complete the valence shell (C) Signup and view all the answers

Which of these are examples of pure elements?

O2 and H2 (A) Signup and view all the answers

What does electronegativity measure?

The ability of an atom to attract shared electrons (B) Signup and view all the answers

Which of these is an example of a nonpolar covalent bond?

CO2 (A) Signup and view all the answers

What is the result of a polar covalent bond?

A molecule with a partial electrical charge (D) Signup and view all the answers

Which of the following is true about ionic bonds?

They involve the transfer of valence electrons (D) Signup and view all the answers

What is the smallest unit of matter that retains the properties of an element?

Atom (A) Signup and view all the answers

Which of the following is NOT an essential element required by all living organisms?

Gold (Au) (C) Signup and view all the answers

What is the atomic number of an element?

The number of protons in an atom (A) Signup and view all the answers

What is the term for different atomic forms of the same element that have different numbers of neutrons?

Isotopes (C) Signup and view all the answers

Which type of isotope has a nucleus that spontaneously decays, giving off particles and energy?

Radioactive Isotopes (B) Signup and view all the answers

What is the half-life of a radioactive isotope?

The time it takes for 50% of the parent isotope to decay (C) Signup and view all the answers

What is the term for the outermost shell of an atom?

Valence Shell (C) Signup and view all the answers

Which of the following elements is an inert element, meaning it is chemically unreactive?

Helium (He) (D) Signup and view all the answers

What is the term for the space where an electron is found 90% of the time?

Orbital (D) Signup and view all the answers

Which of the following statements about electron shells is FALSE?

Electrons in higher energy shells are closer to the nucleus. (C) Signup and view all the answers

What is the maximum number of electrons that can occupy the first electron shell?

2 (D) Signup and view all the answers

What is the key factor that determines the chemical behavior of an atom?

The number of valence electrons in the atom (C) Signup and view all the answers

What is the term for the chemical bond that results from the sharing of electrons between two atoms?

Covalent Bond (A) Signup and view all the answers

What is the term for the chemical bond that results from the transfer of electrons between two atoms?

Ionic Bond (C) Signup and view all the answers

Which of the following is NOT a type of chemical bond?

Gravitational Bond (D) Signup and view all the answers

What is the term for a chemical reaction that releases energy?

Exergonic Reaction (A) Signup and view all the answers

What is the term for a chemical reaction that requires energy input?

Endergonic Reaction (C) Signup and view all the answers

Which of the following compounds would be considered an ionic compound?

Sodium chloride (NaCl) (C) Signup and view all the answers

What type of chemical bond is responsible for the attraction between water molecules?

Hydrogen bond (C) Signup and view all the answers

What is the primary difference between an ionic bond and a covalent bond?

Ionic bonds involve the sharing of electrons, while covalent bonds involve the transfer of electrons. (D) Signup and view all the answers

Which of the following accurately describes a chemical reaction?

A process that involves both breaking and forming chemical bonds. (C) Signup and view all the answers

Which of the following best describes Van der Waals interactions?

Weak attractive forces between molecules due to temporary fluctuations in electron distribution. (D) Signup and view all the answers

Study Notes

Chemical Context of Life

Matter is anything that takes up space and has mass.
Matter is composed of elements.
Elements are substances that cannot be broken down into other substances by chemical reactions.
There are 92 naturally occurring elements.
Elements are represented by symbols (e.g., Gold (Au), copper (Cu), carbon (C)).
Elements can exist in three physical states: solid, liquid, and gas.
Substances whose molecules are arranged in regular, repeating patterns are solids
Molecules in liquids flow easily around one another. Liquids assume the shape of their containers
Molecules in gases fly in all directions at great speeds
The plasma state of matter occurs at very high temperatures, where atoms lose their electrons.
Compounds are substances composed of two or more elements in a fixed ratio.
A compound always has a specific ratio of atoms of different elements. (e.g., water (H₂O), sodium chloride (NaCl)).
Essential elements are required by all living organisms for normal cellular functions.
Essential elements make up ~20-25% and 96% of all living matter.
These elements include oxygen (O), carbon (C), hydrogen (H) and nitrogen (N).
The elements calcium (Ca), phosphorus (P), potassium (K), and sulfur (S) make up ~3.5% .
Trace elements are required by all living organisms for normal cellular functions in very small quantities
Examples: Iron (Fe), Iodine (I), Zinc (Zn)

Atoms

Atoms are the smallest units of matter that retain the properties of an element.
An atom contains subatomic particles: neutrons (no charge), protons (positive charge), and electrons (negative charge).
The nucleus of an atom tightly packs protons and neutrons
Protons determine the atomic number.
Electrons rapidly move around the nucleus
Atomic mass is determined by protons and neutrons.
Atomic mass unit (amu) is also known as Dalton.
Electrons have a much smaller mass than protons or neutrons.

Isotopes

Atoms of the same element can have different numbers of neutrons.
These are called isotopes.
Isotopes have the same atomic number but different mass numbers.
Most naturally occurring elements exist as mixtures of isotopes.
Carbon, for example, has three isotopes: carbon-12, carbon-13, carbon-14.
Carbon-12 is stable, while carbon-13 and carbon-14 are unstable. Carbon-14 is radioactive.
The atomic mass of an element is the weighted average mass of all the naturally occurring isotopes of that element.
Radioactive isotopes undergo spontaneous decay, releasing particles and energy.

Atomic Number and Mass Number

The atomic number of an element is the number of protons in the nucleus of an atom of that element. (e.g., Helium - 2).
Different isotopes of an element will have a different mass number due to the number of neutrons present.
Mass number = number of protons + number of neutrons.

Electron Shells

Electrons occupy specific energy levels or shells.
Electrons farther from the nucleus have higher energy levels.
The first electron shell holds a maximum of 2 electrons. (1s)
The second electron shell holds a maximum of 8 electrons. (2s, 2p).
The third shell holds a maximum of 18 electrons.
Electrons tend to exist in the lowest available states of potential energy.

Valence Shell

The valence shell is the outermost electron shell of an atom.
Valence electrons are the electrons present in the outermost electron shell.
The number of valence electrons determines the chemical behavior of the atom.
Atoms with the same number of valence electrons show similar chemical behavior.

Inert Elements

Inert elements are chemically unreactive elements that have completely filled valence electron shells.
Example: Helium, Neon, Argon, Krypton, Xenon, and Radon.

Electron Orbitals

Electron orbitals describe the space where an electron is found 90% of the time.
Unlike electron shells, orbital depicts complex, 3D shapes of electron distribution in space
An electron can exist in different orbitals of the same energy level.

Chemical Bonding

Chemical bonds are interactions between atoms in order to form chemical compounds
Covalent bonds are formed when atoms share valence electrons. This results in molecules.
Ionic bonds are formed when one atom loses one or more electrons and another atom gains them. This results in ions that attract to each other.
Hydrogen bonds form when a hydrogen atom covalently bonded to a highly electronegative atom (such as oxygen or nitrogen) is attracted to another electronegative atom or molecule.
Van der Waals forces are very weak attractions between molecules that are close together.

Chemical Reactions

Chemical reactions involve changing the composition of a substance by making or breaking chemical bonds, where reactant materials change into product materials.
Reactants are the materials that start the chemical reaction, while products are the result of the chemical reaction.
Coefficients show the quantity of each molecule involved.
The number of atoms in reactants must equal the number of atoms in the products and the overall charged need to be equal. This reflects the law of conservation of mass.

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Description

Test your knowledge on atomic interactions, chemical bonds, and the properties of elements in this quiz on Chemistry Chapter 2. Explore concepts like covalent bonds, electronegativity, isotopes, and more to solidify your understanding of essential chemistry topics.