The four most common elements in living organisms are

• C, H, O, Fe.

• C, H, O, Na.

• C, H, O, N.

• C, N, O, Na.

Which of the following is a trace element in the human body?

• nitrogen

• zinc

• oxygen

• hydrogen

Which of the following statements regarding matter is false?

• All life is composed of matter.

• All matter has mass.

• All matter is composed of elements.

• All matter exists in the form of compounds.

Which of the following statements best describes a compound?

• A compound is a pure element.

• A compound contains two or more different elements in a fixed ratio

• A compound is exemplified by sodium.

• A compound is a solution.

In the equation 2 H2 + O2 → 2 H2O,

• H2, O2, and H2O are all compounds.

• H2, O2, and H2O are all elements.

• only H2O is a compound.

• only H2 and O2 are compounds.

Tags

NGSS.MS-PS1-1

Which of the following trace elements needed by humans is commonly added to table salt?

• iodine

• iron

• magnesium

• fluoride

In some areas, fluoride is added during the municipal water treatment process in order to help

• prevent goiter

• prevent the growth of bacteria

• prevent the development of mental retardation

• reduce tooth decay

Which of the following particles is found in the nucleus of an atom?

• protons and neutrons

• protons and electrons

• only protons

• only electrons

Tags

NGSS.HS-PS1-8

Electrons move about the nucleus of an atom in the same way that

• insects fly around a bright lamp at night.

• cars are parked along the sides of a street.

• boats cross a lake.

• birds migrate to a new winter home.

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons?

• 6

• 8

• 12

• 18