Chapter 2: The Chemical Context of Life

About 25 of the 92 natural Elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?

• Carbon, sodium, hydrogen, nitrogen

• carbon, oxygen, phosphorus, hydrogen

• Oxygen, hydrogen, calcium, nitrogen

• Carbon, hydrogen, nitrogen, oxygen

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?

• Calcium

• Iodine

• Sodium

• Phosphorus

Which of the following statements is TRUE?

• Carbon, hydrogen, oxygen, and calcium are the most abundant elements of living matter.

• Some naturally occurring elements are toxic to organisms.

• All life requires the same essential elements.

• A patient suffering from a goiter should not consume seafood.

Which of the following are compounds?

• H2O, O2, and CH4

• H2O and O2

• O2 and CH4

• H2O and CH4, but not O2

Atoms have no electric charge because they have ________.

• uncharged neutrons in their nuclei

• an equal number of protons and neutrons

• an equal number of protons and electrons

• an equal number of charged and uncharged subatomic particles

Tags

NGSS.HS-PS1-7

An ion with six protons, seven neutrons, and a charge of 2+ has an atomic number of ________.

• four

• five

• six

• seven

Tags

NGSS.MS-PS1-1

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Which of the following can be true?

• Molybdenum atoms can have between 50 and 58 neutrons.

• Molybdenum atoms can have between 50 and 58 protons.

• Molybdenum atoms can have between 50 and 58 electrons.

• Isotopes of molybdenum have different numbers of electrons.

Tags

NGSS.MS-PS1-1

Carbon-14 has the same ________.

• atomic number and atomic mass as carbon-12

• atomic number and thus number of neutrons as carbon-13

• atomic mass as both carbon-12 and carbon-13

• number of protons but more neutrons than carbon-12

A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge.

• proton; neutron

• neutron; proton

• neutron; electron

• electron; neutron

Tags

NGSS.HS-PS1-8

The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains ________.

• 7 neutrons

• 8 neutrons

• 8 protons

• 15 protons

Tags

NGSS.MS-PS1-1