Ch 3 the building blocks of life

What defines matter?

Anything that has mass and takes up space

What is the basic structural unit of all living things?

Cell

What are the three main states of matter?

Solid, liquid, and gas

What are atoms composed of?

Protons, neutrons, and electrons

What organizes elements on the periodic table?

Atomic number

What is the atomic symbol for oxygen?

O

What does the nucleus of an atom contain?

Protons and neutrons

On what basis does science operate?

Observation, experimentation, and evidence

What do isotopes of an element have in common?

The same number of protons but different numbers of neutrons

What results in radioactivity?

Unstable atomic nuclei

What do electrons occupy?

Energy levels or shells

What does nuclear medicine use for diagnosis and treatment?

Radioactive isotopes

What does a chemical change result in?

The formation of a new substance

How are ionic compounds formed?

Transfer of electrons

What is the correct formula for sodium chloride?

NaCl

What does a polyatomic ion consist of?

Two or more atoms with a charge

What do covalent bonds involve?

Sharing of electrons

What do water molecules exhibit?

Hydrogen bonding

What must a chemical reaction be?

Balanced

What does an anabolic reaction do?

Builds larger molecules from smaller ones

What does a catabolic reaction do?

Breaks down molecules

What does oxidation involve?

Loss of electrons

What do acids donate?

Protons (H⁺ ions)

What do buffers help maintain?

pH balance

What causes acid reflux?

Stomach acid moving into the esophagus

What are electrolytes essential for?

Nerve and muscle function

Why is water essential to life?

Supports biochemical reactions

What allows for cohesion and adhesion in water?

The polarity of water molecules

What is the chemical formula of water?

H₂O

What is the pH of pure water?

7