Biology 111 Chapter 2

What is matter?

• Anything that occupies space and has mass

• Anything that produces energy

• A substance that cannot change form

• An object that reflects light

Which of the following best describes an element?

• A substance consisting of two or more atoms

• A pure substance containing only one type of atom

• A compound formed by chemical reactions

• A mixture of different atoms in fixed ratios

Which four elements make up 96% of living matter?

• Carbon, Hydrogen, Oxygen, Phosphorus

• Carbon, Hydrogen, Oxygen, Nitrogen

• Nitrogen, Hydrogen, Phosphorus, Oxygen

• Carbon, Oxygen, Calcium, Iron

What is the smallest unit of matter that still retains the properties of an element?

• Molecule

• Compound

• Atom

• Ion

Which subatomic particle has a positive charge?

• Electron

• Proton

• Neutron

• Photon

What determines the atomic number of an element?

• The number of neutrons in the nucleus

• The total number of protons and neutrons

• The number of protons in the nucleus

• The number of electrons in orbitals

How is the mass number of an atom calculated?

• Sum of protons and electrons

• Number of protons

• Number of neutrons

• Sum of protons and neutrons

What are isotopes?

• Atoms of the same element with different numbers of protons

• Atoms of the same element with different numbers of electrons

• Atoms of the same element with different numbers of neutrons

• Atoms of different elements with the same number of protons

What is a radioisotope?

• An isotope with excess energy that emits radiation

• An atom that has gained or lost electrons

• A stable isotope that does not decay

• A positively charged ion

Which type of radiation has the highest energy and can penetrate thick layers of lead?

• Alpha particles

• Beta particles

• Gamma rays

• X-rays