Smith 1

What are the three main subatomic particles?

Protons (positive), neutrons (neutral), and electrons (negative).

Where are protons, neutrons, and electrons located?

Protons and neutrons are in the nucleus; electrons are around the nucleus.

What is an element?

A pure substance made of one type of atom.

What is the atomic number?

The number of protons in an atom.

What is the mass number?

The total number of protons and neutrons.

How do you calculate the number of neutrons?

Subtract the atomic number from the mass number.

What are isotopes?

Atoms of the same element with different numbers of neutrons.

What is an ion?

An atom that gains or loses electrons.

What happens when an atom loses or gains electrons?

Losing electrons makes it positive; gaining electrons makes it negative.

What is a molecule?

Two or more atoms chemically bonded together.

What is a compound?

Two or more different elements chemically bonded together.

What is the difference between molecules and compounds?

Molecules can contain the same or different elements; compounds contain different elements.

How many atoms are in H₂O and CO₂?

H₂O has 2 hydrogen and 1 oxygen; CO₂ has 1 carbon and 2 oxygen.

How many atoms are in NH₃ and N₂O?

NH₃ has 1 nitrogen and 3 hydrogen; N₂O has 2 nitrogen and 1 oxygen.

What are the four main elements in living matter?

Oxygen, carbon, hydrogen, and nitrogen.

What are valence electrons?

Electrons in an atom's outermost energy level.

How many electrons fit in the first and second energy levels?

The first holds 2; the second holds 8.

What is an ionic bond?

A bond formed when electrons transfer from one atom to another.

What is a covalent bond?

A bond formed when atoms share electrons.

What is a chemical reaction?

A process in which atoms recombine to form new substances.

What are reactants and products?

Reactants are the starting substances; products are the substances formed.

What are organic and inorganic compounds?

Organic compounds contain carbon; inorganic compounds generally do not contain carbon.

What is cohesion vs. adhesion?

Cohesion is attraction between molecules of the same substance; adhesion is attraction between different substances.

What is an alveolus, and what happens there?

A tiny air sac in the lungs where oxygen and carbon dioxide are exchanged.

Why are alveolar walls thin?

To allow oxygen and carbon dioxide to move quickly between air and blood.

What is pulmonary surfactant?

A substance that reduces surface tension in the alveoli.

What does pulmonary surfactant do?

It helps prevent alveoli from sticking together and collapsing.

Which cells produce pulmonary surfactant?

Type II alveolar cells.

What is IRDS, and who is most at risk?

Infant respiratory distress syndrome; premature babies are at risk because their lungs may not produce enough surfactant.

What is DPPC?

A major component of pulmonary surfactant; its head is attracted to water, and its tails repel water.