How many electrons does nitrogen have in its valence shell?
A)
2
B) 5
C) 7
D) 8
E) 14
B
About twelve to twenty-four hours after the previous meal, a person's blood-sugar level normally varies from 60 to 90 milligrams per 100 milliliters of blood, though it may rise to 130 mg/100 ml after meals high in carbohydrates. That the blood-sugar level is maintained within a fairly narrow range despite uneven intake of sugar is due to the body's ability to carry out
a.adaptation.
b.inheritance.
c.metabolism.
d.homeostasis.
e.all of these
D
In ammonium chloride salt (NH4Cl) the anion is a single chloride ion,
Cl-. What is the cation of NH4Cl?
A) N, with a charge of
+3
B) H, with a charge of +1
C) H2 with a charge of
+4
D) NH4 with a charge of +1
E) NH4 with a charge of +4
D
Water molecules are able to form hydrogen bonds with
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar
covalent bonds.
D) ionic bonds.
E) van der Waals interactions.
C
All the organisms on your campus make up
a. ecosystem
b. community
c. population
d. an experimental group
e. a taxonomic domain
B
Why is a helium atom (atomic number; 2) more stable than a hydrogen atom (atomic number; 1)?The three most common atoms in the human body are
a.Two electrons completely fill its outermost electron shell.
b.Eight electrons completely fill its outermost electron shell.
c.The outermost electron shell is half-empty.
d. Helium atoms react readily with oxygen.
e.Hydrogen atoms react to form helium.
A
The three most common atoms in the human body are
...