What is the molecular structure of water described as?
A tetrahedron, with δ- at the H and δ+ at the O.
Where are protons and neutrons located in an atom?
In the nucleus.
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p.9
Hydrogen Bonds and Water's Polarity

What is the molecular structure of water described as?

A tetrahedron, with δ- at the H and δ+ at the O.

p.1
Atomic Structure and Isotopes

Where are protons and neutrons located in an atom?

In the nucleus.

p.1
Atomic Structure and Isotopes

What is unique about hydrogen in terms of atomic structure?

It usually has 1 proton and no neutrons.

p.3
Atomic Structure and Isotopes

What is the lowest energy level or electron shell called?

Energy level K.

p.5
Covalent and Ionic Bonds

What keeps Na+ and Cl− associated in an ionic compound?

The attraction of opposite charges.

p.7
Hydrogen Bonds and Water's Polarity

What type of charge do hydrogen atoms in water have?

Slightly positive charge.

p.5
Covalent and Ionic Bonds

What forms ionic bonds?

The attraction of oppositely charged ions.

p.1
Nature of Atoms

What is the definition of matter?

Any substance in the universe that has mass and occupies space.

p.1
Atomic Structure and Isotopes

What charge do electrons have?

Negatively charged.

p.4
Elements in Living Systems

What do valence electrons determine?

The type of interaction that can occur between atoms.

p.11
Acids and Bases

How does the strength of an acid relate to its pH?

The stronger an acid is, the more hydrogen ions it produces and the lower its pH.

p.11
Acids and Bases

What is a base?

A substance that combines with H+ dissolved in water, thus lowering the [H+].

p.3
Atomic Structure and Isotopes

What orbitals are present in energy level L?

2s (2 electrons) and 2p (6 electrons in pairs).

p.3
Atomic Structure and Isotopes

Why is the Neon atom considered unreactive?

Because its energy levels K and L are completely filled with electrons.

p.6
Covalent and Ionic Bonds

What is electronegativity?

An atom's affinity for electrons.

p.5
Covalent and Ionic Bonds

What happens to a sodium atom when it forms an ionic bond?

It loses an electron to become Na+.

p.8
Covalent and Ionic Bonds

What results in an ionic bond?

A transfer of electrons, creating positive and negative ions that attract each other.

p.8
Covalent and Ionic Bonds

What defines a covalent bond?

The sharing of electrons between two atoms.

p.8
Covalent and Ionic Bonds

What is a polar covalent bond?

A bond involving unequal sharing of electrons, resulting in regions of partial charge.

p.11
Acids and Bases

What is the overall effect of buffers on [H+]?

Buffers keep [H+] relatively constant and minimize changes in pH.

p.9
Properties of Water

What is the specific heat of water?

1 calorie/g/°C.

p.7
Hydrogen Bonds and Water's Polarity

What are the weak attractions between water molecules called?

Hydrogen bonds.

p.11
Acids and Bases

What is an acid?

Any substance that dissociates in water to increase the [H+] and lower the pH.

p.3
Atomic Structure and Isotopes

What orbital occupies energy level K?

A single s orbital called 1s.

p.3
Atomic Structure and Isotopes

How many electrons can energy level L contain?

Up to 8 electrons.

p.9
Properties of Water

What is the difference between cohesion and adhesion in water?

Cohesion is the attraction between water molecules, while adhesion is the attraction between water molecules and other polar molecules.

p.6
Covalent and Ionic Bonds

What characterizes nonpolar covalent bonds?

Equal sharing of electrons.

p.7
Hydrogen Bonds and Water's Polarity

What type of charge does the oxygen atom in water have?

Slightly negative charge.

p.12
Covalent and Ionic Bonds

What do ionic bonds arise from?

Attractions between ions of opposite charge.

p.5
Covalent and Ionic Bonds

What happens to a chlorine atom when it forms an ionic bond?

It gains an electron to become Cl−.

p.6
Covalent and Ionic Bonds

What forms covalent bonds?

When atoms share 2 or more valence electrons.

p.4
Elements in Living Systems

How many naturally occurring elements are there?

94 naturally occurring elements.

p.8
Chemical Reactions and Energy

What do reactants and products represent in a chemical reaction?

Reactants are the original molecules, and products are the molecules resulting from the reaction.

p.11
Acids and Bases

What do most biological buffers consist of?

A pair of molecules, one an acid and one a base.

p.9
Properties of Water

Why does water require a large amount of energy to change temperature?

Because of the many hydrogen bonds that need to be broken.

p.7
Hydrogen Bonds and Water's Polarity

What results in weak electrical attractions between neighboring water molecules?

The polarity of water.

p.1
Nature of Atoms

Why is understanding atomic structure important?

It is critical to understanding the nature of biological molecules.

p.4
Elements in Living Systems

What is the octet rule?

Atoms tend to establish completely full outer energy levels, typically one filled s orbital and three filled p orbitals.

p.4
Elements in Living Systems

Which element is an exception to the octet rule?

Helium, which has only one shell with 2 electrons.

p.11
Acids and Bases

What is the function of buffers?

Buffers resist changes in pH by releasing hydrogen ions when a base is added and absorbing hydrogen ions when acid is added.

p.9
Properties of Water

What phenomenon allows water to rise in a narrow tube?

Capillary action, due to adhesion of water molecules to the sides of the tube.

p.3
Atomic Structure and Isotopes

What happens to an electron when an atom absorbs energy?

The electron moves to a higher energy level, farther from the nucleus.

p.8
Hydrogen Bonds and Water's Polarity

Why is water considered a polar molecule?

Because the bonds between oxygen and hydrogen are highly polar, with oxygen being more electronegative.

p.6
Covalent and Ionic Bonds

Why is water (H2O) considered a polar molecule?

Oxygen has a greater affinity for electrons than hydrogen, leading to unequal sharing.

p.2
Nature of Atoms

What does the atomic number represent?

The number of protons in an atom.

p.2
Nature of Atoms

What are isotopes?

Atoms of a single element that possess different numbers of neutrons.

p.2
Nature of Atoms

How many electrons can an orbital contain?

No orbital can contain more than two electrons.

p.3
Atomic Structure and Isotopes

What are the energy levels of electrons denoted by?

Letters starting with K, L, M, etc.

p.1
Nature of Atoms

What significant event occurred approximately 12.5 billion years ago?

An enormous explosion that probably signaled the beginning of the universe.

p.1
Nature of Atoms

When did life begin on Earth?

Approximately 3.5 billion years ago.

p.6
Covalent and Ionic Bonds

What is the result of forming covalent bonds?

No net charge, satisfies the octet rule, and no unpaired electrons.

p.4
Elements in Living Systems

Which four elements make up 96.3% of human body weight?

Carbon, hydrogen, oxygen, and nitrogen.

p.8
Chemical Reactions and Energy

What factors influence the extent of a chemical reaction?

Temperature, concentration of reactants and products, and catalysts.

p.3
Chemical Reactions and Energy

What is oxidation in terms of electron transfer?

Loss of an electron.

p.4
Elements in Living Systems

What is the significance of trace elements in living organisms?

Some trace elements are very important for biological functions.

p.10
Properties of Water

What is hydrophobic exclusion?

The process by which water organizes nonpolar molecules, causing them to aggregate.

p.2
Nature of Atoms

What are ions?

Charged particles that are unbalanced in terms of protons and electrons.

p.1
Atomic Structure and Isotopes

What are the three main components of an atom?

Protons, neutrons, and electrons.

p.12
Acids and Bases

What is a solution with a high concentration of hydrogen ions called?

An acid.

p.12
Acids and Bases

What is the pH of a solution with a high concentration of hydrogen ions?

It has a low pH.

p.12
Covalent and Ionic Bonds

How many covalent bonds could an atom form if it can form four?

Four.

p.12
Hydrogen Bonds and Water's Polarity

What is true about a molecule with polar covalent bonds?

It would be soluble in water.

p.6
Covalent and Ionic Bonds

What is the effect of sharing electrons in covalent bonds?

It fills the valence electron energy level, making bonded atoms more stable.

p.4
Elements in Living Systems

What are the characteristics of inert (nonreactive) elements?

They have all eight electrons in the valence shell.

p.3
Chemical Reactions and Energy

What is reduction in terms of electron transfer?

Gain of an electron.

p.10
Properties of Water

Why is solid water (ice) less dense than liquid water?

Because hydrogen bonds in ice space the water molecules relatively far apart.

p.2
Nature of Atoms

How is atomic mass calculated?

It is the sum of protons and neutrons in an atom.

p.2
Nature of Atoms

What does the Bohr model describe?

Electrons in discrete orbits around the nucleus.

p.9
Hydrogen Bonds and Water's Polarity

What type of bonds form between water molecules?

Hydrogen bonds.

p.9
Properties of Water

What property of water allows it to have high surface tension?

Cohesion, due to hydrogen bonding between water molecules.

p.6
Covalent and Ionic Bonds

What determines the strength of a covalent bond?

The number of shared electrons.

p.5
Covalent and Ionic Bonds

What is formed due to the electrostatic attraction of oppositely charged ions?

A lattice of Na+ and Cl−.

p.8
Hydrogen Bonds and Water's Polarity

What is the most outstanding chemical property of water?

Its ability to form hydrogen bonds.

p.9
Hydrogen Bonds and Water's Polarity

What is the cumulative effect of hydrogen bonds in water?

They are responsible for many of water's important physical properties.

p.10
Properties of Water

What ecological importance does the density of ice have?

It allows ice to float, keeping the water beneath liquid and protecting aquatic life.

p.2
Nature of Atoms

What is the difference between mass and weight?

Mass refers to the amount of substance, while weight refers to the force of gravity on that substance.

p.5
Covalent and Ionic Bonds

How can water molecules affect ionic bonds?

They can disrupt the forces holding ions together.

p.5
Covalent and Ionic Bonds

What occurs when Na donates an electron to Cl?

Na is oxidized and Cl is reduced.

p.4
Nature of Atoms

What are compounds?

Molecules containing more than one type of element.

p.11
Acids and Bases

What is blood acidosis?

A condition where human blood pH drops from the normal 7.4 to ~7.1, which can be fatal if not treated.

p.6
Covalent and Ionic Bonds

What characterizes polar covalent bonds?

Unequal sharing of electrons.

p.10
Properties of Water

What types of substances are soluble in water?

Polar molecules and ions, such as sugar and salt.

p.2
Nature of Atoms

What are electrons?

Negatively charged particles located in orbitals that occupy most of the volume of the atom.

p.2
Nature of Atoms

What is half-life?

The time it takes for half of the atoms in a sample to decay.

p.12
Covalent and Ionic Bonds

What type of atoms does a molecule with polar covalent bonds contain?

Atoms with very different electronegativity.

p.5
Covalent and Ionic Bonds

What are the charged forms of sodium and chlorine in ionic bonding?

Sodium becomes a cation (Na+) and chlorine becomes an anion (Cl−).

p.11
Acids and Bases

What is blood alkalosis?

A condition where blood pH rises up to 7.7, which is also serious.

p.10
Properties of Water

How does the evaporation of water facilitate cooling?

It cools the surface from which it evaporates, such as in sweating.

p.2
Nature of Atoms

Define an element.

A substance that cannot be broken down into simpler substances by ordinary chemical means.

p.2
Nature of Atoms

How do electrons determine the chemical behavior of atoms?

The number and arrangement of electrons in their orbitals are key to an atom's chemical behavior.

p.4
Elements in Living Systems

What do elements in the same column of the periodic table have in common?

They have the same number of valence electrons.

p.10
Properties of Water

What is the heat of vaporization of water?

586 calories per gram.

p.2
Nature of Atoms

What is the relationship between protons and electrons in neutral atoms?

They have the same number of protons and electrons.

p.2
Nature of Atoms

What is a radioactive isotope?

An unstable isotope that emits radiation as its nucleus breaks up.

p.8
Hydrogen Bonds and Water's Polarity

What partial charges develop within a water molecule?

Oxygen becomes partially negative (δ–) and hydrogen becomes partially positive (δ+).

p.10
Properties of Water

What happens to the covalent bond in a water molecule?

It can be spontaneously broken, leading to ionization.

p.2
Nature of Atoms

What is a cation?

A particle with more protons than electrons, resulting in a net positive charge.

p.3
Chemical Reactions and Energy

What is stored in high-energy electrons during redox reactions?

Chemical energy.

p.10
Acids and Bases

What is the pH of pure water at 25 °C?

Neutral, with a [H+] of 10^-7.

p.2
Nature of Atoms

What is an anion?

A particle with fewer protons than electrons, resulting in a net negative charge.

p.2
Nature of Atoms

What is the modern definition of an orbital?

An area around a nucleus where an electron is most likely to be found.

Study Smarter, Not Harder
Study Smarter, Not Harder