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Flashcards in Ch 2 Deck (9)
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1
Q

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

A

Carbon, hydrogen, nitrogen, oxygen

2
Q

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?

A

Iodine

3
Q

Which of the following statements is false?

A

Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge.

4
Q

Each element is unique and different from other elements because of the number of protons n the nuclei of its atoms. Which of the following indicates the number of protons in an atoms nucleus?

A

atomic number

5
Q

One difference between carbon-12 (12, 6 C) and carbon-14 (14, 6 C) is that carbon-14 has

A

two more neutrons than carbon-12

6
Q

3His a radioactive isotope of hydrogen. One difference between hydrogen-1 (1, 1 H) and hydrogen-3 (3, 1 H) is that hydrogen-3 has

A

two more neutrons than hydrogen-1.

7
Q

The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon-14 contains _____ neutrons.

A

8

8
Q

Two isotopes of the same element will have different numbers of

A

neutrons

9
Q

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that

A

an electron may move to an electron shell farther out from the nucleus