{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

HL IB Biology 3 wk test

HL IB Biology 3 wk test - HL IB Biology 3 wk test Multiple...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
HL IB Biology 3 wk test Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. ____ 1. 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, sodium, chlorine, nitrogen b. carbon, sulfur, phosphorus, hydrogen c. oxygen, hydrogen, calcium, sodium d. carbon, hydrogen, nitrogen, oxygen e. carbon, oxygen, sulfur, calcium ____ 2. 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? ____ 3. Atoms whose outer electron shells contain eight electrons tend to a. form ionic bonds in aqueous solutions. b. form covalent bonds in aqueous solutions. c. be stable and chemically nonreactive, or inert. d. be unstable and chemically very reactive. e. be isotopes and very radioactive. ____ 4. What do the four elements most abundant in life-carbon, oxygen, hydrogen, and nitrogen-have in common? a. They all have the same number of valence electrons. b. Each element exists in only one isotopic form. c. They are equal in electronegativity. d. They are elements produced only by living cells. e. They all have unpaired electrons in their valence shells. ____ 5. In a single molecule of water, the two hydrogen atoms are bonded to a single oxygen atom by ____
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}