Chapter 2: Basic Chemistry – Elements, Molecules, Water, and Bonding

A set of practice flashcards covering key concepts from Chapter 2: Basic Chemistry (elements, atoms, bonding, molecules, and water).

What is matter?

Matter is anything that has mass and occupies space.

What are the four states of matter?

Solid, liquid, gas, or plasma.

What is an element?

A substance that cannot be broken down into substances with different properties; composed of one type of atom.

What does CHNOPS stand for?

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.

What is a molecule of an element?

A molecule made of two or more atoms of the same element bonded together.

What is a molecule?

Two or more of the same type of atoms bonded together; the smallest part of a compound that retains its chemical properties.

What is a compound?

A molecule containing at least two different elements bonded together.

What does a chemical formula tell you?

The number of each kind of atom in a molecule.

What are protons, neutrons, and electrons?

Subatomic particles: protons (+) and neutrons (neutral) in the nucleus; electrons (-) in electron shells.

Where is the nucleus located and what does it contain?

In the center of the atom; contains protons and neutrons.

Where are electrons located?

In electron shells surrounding the nucleus.

What is the atomic number?

The number of protons in an atom (and, in a neutral atom, the number of electrons).

What is the mass number?

The sum of the protons and neutrons in the nucleus; atomic mass is approximately equal to the mass number.

What is an isotope?

Atoms of the same element that differ in the number of neutrons (and thus mass).

What is a period in the periodic table?

A horizontal row of elements arranged by increasing atomic number.

What is a group in the periodic table?

A vertical column; elements in a group share the same chemical bonding characteristics.

What are noble gases?

Group VIII elements that are inert.

What does the atomic number tell you?

The number of protons; in a neutral atom it also equals the number of electrons.

What is a valence shell?

The outermost energy shell of an atom.

What is the octet rule?

Outer shell is most stable when it has eight electrons; exception: atoms with only one shell are stable with two electrons.

What determines whether an atom gives up, accepts, or shares electrons?

The number of electrons in its valence shell; a full valence shell means stability, an incomplete one means reactivity.

What is a covalent bond?

A bond formed by sharing a pair of valence electrons so each atom achieves an octet; can be nonpolar or polar.

What is a nonpolar covalent bond?

Electrons are shared equally between atoms.

What is a polar covalent bond?

Electrons are shared unequally due to differences in electronegativity.

What is an ionic bond?

A bond formed by transfer of electrons resulting in oppositely charged ions that attract.

What is an ion?

An atom that has gained or lost electrons.

What is a salt?

Solid substances that usually exist as individual ions in water.

What is electronegativity?

The ability of an atom to attract electrons toward itself in a chemical bond.

Why is water polar?

Oxygen is more electronegative than hydrogen, causing the O–H bonds to be polar.

What does C6H12O6 indicate?

One molecule of glucose containing 6 carbon, 12 hydrogen, and 6 oxygen atoms.