BIOL 101: Exam 1: Chapter 2 Review Questions

If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have? A. 54 B. 27 C. 100 D. 108

A. 54

When acids are added to a solution, the pH should ________. A. decrease B. increase C. stay the same D. cannot tell without testing

A. decrease

Which type of bond represents a weak chemical bond? A. hydrogen bond B. atomic bond C. covalent bond D. nonpolar covalent bond

A. hydrogen bond

Which of the following statements is true? A. Acids and bases cannot mix together. B. Acids and bases will neutralize each other. C. Acids, but not bases, can change the pH of a solution. D. Acids donate hydroxide ions (OH-); bases donate hydrogen ions (H+).

C. Acids, but not bases, can change the pH of a solution.

We call a molecule that binds up excess hydrogen ions in a solution a(n) ________. A. acid B. isotope C. base D. donator

C. base

Potassium has an atomic number of 19. What is its electron configuration? A. shells 1 and 2 are full, and shell 3 has nine electrons B. shells 1, 2 and 3 are full and shell 4 has three electrons C. shells 1, 2 and 3 are full and shell 4 has one electron D. shells 1, 2 and 3 are full and no other electrons are present

C. shells 1, 2 and 3 are full and shell 4 has one electron

What property of carbon makes it essential for organic life?

Carbon is unique and found in all living things because it can form up to four covalent bonds between atoms or molecules. These can be nonpolar or polar covalent bonds, and they allow for the formation of long chains of carbon molecules that combine to form proteins and DNA.

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12 has six neutrons. Carbon-13 has seven neutrons.

An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. Looking at this figure, how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?

Elements in group 1 need to lose one electron to achieve a stable electron configuration. Elements in groups 14 and 17 need to gain four and one electrons, respectively, to achieve a stable configuration.

What makes ionic bonds different from covalent bonds?

covalent bond - formed when two atoms share electrons. - Covalent bonds have an electronegativity difference that is less than 2. Ionic Bonds - are forces that hold together electrostatic forces of attractions between oppositely charged ions. - Have an electronegativity difference greater than or equal to 2.

Which of the following statements is not true? A. Water is polar. B. Water stabilizes temperature. C. Water is essential for life. D. Water is the most abundant molecule in the Earth's atmosphere.

D. Water is the most abundant molecule in the Earth's atmosphere.

Each carbon molecule can bond with as many as________ other atom(s) or molecule(s). A. one B. two C. six D. four

D. four

Atoms that vary in the number of neutrons found in their nuclei are called ________. A. ions B. neutrons C. neutral atoms D. isotopes

D. isotopes

Why are hydrogen bonds and van der Waals interactions necessary for cells?

Form weak associations between different molecules or within different regions of the same molecule. They provide the structure and shape necessary for proteins and DNA within cells so that they function properly.