Ch 2

The four most abundant elements in living organisms are:

• carbon, hydrogen, potassium, and oxygen.

• hydrogen, nitrogen, carbon, and silicon.

• carbon, nitrogen, hydrogen, and calcium.

• hydrogen, nitrogen, oxygen, and carbon.

• carbon, hydrogen, nitrogen, and phosphorus

Carbon-14 has the same:

• number of protons but more neutrons than carbon-12.

• atomic number and atomic mass as carbon-12.

• atomic number and, therefore, the same number of neutrons as carbon-13.

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

• carbon, hydrogen, nitrogen, and phosphorus

All matter on earth, both living and non-living, is made up of:

• cells.

• DNA

• carbohydrates.

• phospholipids.

• atoms.

Of all the elements that occur on earth, how many are found in your body?

• 4

• 10

• 25

• 90

• 100

The thing that distinguishes one element, such as chlorine, from another, such as neon, is the number of:

• protons in the nucleus.

• protons and neutrons in the nucleus.

• electrons.

• protons, neutrons, and electrons.

• neutrons in the nucleus.

What would happen if you subdivided an atom of sodium?

• You would form salt.

• The pieces would come together in a uniform, crystal structure.

• The particle of matter would lose its essential properties.

• You would have two atoms of sodium.

• You would create an additional electron shell.

True or False: A piece of silver can be cut indefinitely into pieces and still retain all of the properties of silver.

• True. All particles, including subatomic particles that make up the element, possess the properties of the element.

• True. Atoms are the smallest units of matter, are indivisible, and possess the properties of their element.

• False. Once the pieces are smaller than an atom of silver, the pieces no longer retain the properties of silver.

• False. Silver atoms are too small to possess the properties of silver.

• False. As a piece of silver is cut into smaller pieces, the atoms begin to take on the properties of smaller

  elements.

Which statement describes an atom of oxygen?

• Most naturally occurring atoms of oxygen contain 9 neutrons.

• All atoms of oxygen include 8 protons.

• Nitrogen-15 is an isotope of oxygen.

• Its atomic weight is the same as its atomic mass.

• Its chemical symbol is Ox.

Carbon:

• has no vacancies in its outermost shell.

• can form up to 4 bonds with other atoms.

• can’t form bonds with other atoms of carbon.

• can hold 4 electrons in its first electron shell.

• is the least reactive of all elements.

Which of these atoms is most likely to be involved in a chemical reaction?

• helium (atomic number 2)

• potassium (atomic number 19)

• neon (atomic number 10)

• argon (atomic number 18)

• xenon (atomic number 54)