Chapter Two: Chemistry of Life

Matter

Composed of everything and has volume and mass

Atom

Smallest unit of an element that contains an atomic nucleus of protons and neutrons with electrons that orbit it

Molecule

Two or more atoms chemically bonded together

Element

A substance defined by the number of protons

Compound

Two or more elements chemically bonded to make a new substance

What is the unit of mass of a proton?

One

What is the charge of a proton?

+1

What is a proton part of?

The atomic nucleus

What is the unit of mass of a neutron?

One

What is the charge of a neutron?

None

What is a neutron a part of?

The atomic nucleus

What is the unit of mass of an electron?

None

What is the charge of an electron?

-1

What do electrons do?

Orbit the atomic nucleus

How do subatomic particles attract and repel each other?

Positive charges attract negative charges (e.g., protons attract electrons), and similar charges repel each other (e.g., electrons and electrons)

Valence shell

The outermost shell of an atom containing electrons

Fill in the blank diagram

a. Electrons

b. Atomic nucleus

c. Neutrons

d. Protons

Octet rule

The inner shell contains two electrons, and the valence shell contains eight

What is an example of a noble gas?

Helium (He)

Reactive atom

An atom that is not inert (does not have a filled valence shell) which makes it unstable

What determines the size of an atom?

Number of protons

Atomic number

The amount of protons in the atomic nucleus

Atomic mass

The amount of protons and neutrons in the atomic nucleus

Isotope

One of two or more atoms with the same protons (atomic number) but with different numbers of neutrons (atomic mass)

Neutral atom

An atom with the same number of electrons as protons (the charges equal each other)

What is an example of a neutral atom?

Carbon (C) has six protons and six electrons

Ion

An atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons

What does it mean to have a positive ion (cation)?

An electron(s) is lost (more protons than electrons)

What does it mean to have a negative ion (anion)?

An electron(s) is gained (more electrons than protons)

What is needed for chemicals to bond?

Energy

What is created when chemical bonds are broken?

Energy

Ionic bond

A chemical bond where one or more electrons are transferred creating oppositely charged ions that attract each other

What is an example of an ionic bond?

Sodium chloride (NaCI) or table salt

Covalent bond

A type of chemical bond where two atoms are connected to each other by the sharing of two or more electrons

Polar covalent bond

A chemical bond with unequal sharing of electrons and unequal charges

What is an example of a polar covalent bond?

Water (H₂O)

Non-polar covalent bond

A chemical bond with equal sharing of electrons and equal charges

What is an example of non-polar covalent bond?

Hydrogen gas (H₂)

Hydrogen bond

A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially a nitrogen, oxygen, or fluorine atom, usually of another molecule