LIFESCI 7A midterm 1 Exam Questions with Correct Answers Latest Update 2025-2026
Which of the following CORRECTLY pairs the particles of an atom with their physical properties?
proton-positively charged; neutron-uncharged; electron-negatively charged
proton-negatively charged; neutron-uncharged; electron-positively charged
proton-positively charged; neutron-negatively charged; electron-uncharged
proton-uncharged; neutron-negatively charged; electron-positively charged - Answers proton-
positively charged; neutron-uncharged; electron-negatively charged
For an atom that is NOT an ion, which of the following must be TRUE?
The number of electrons equals the number of neutrons.
The number of protons equals the number of neutrons.
The number of electrons equals the number of protons. - Answers The number of electrons
equals the number of protons.
Sometimes, atoms gain or lose particles. The loss of which of the following would result in a
change of overall electrical charge?
protons only
neutrons only
electrons only
protons or electrons
protons or neutrons
neutrons or electrons - Answers protons or electrons
Sometimes, atoms gain or lose particles. The loss of which of the following results in a change
of atomic mass?
a neutron and a proton
a neutron
,an electron
a proton
a proton and an electron - Answers a neutron and a proton
A polar bond is due to:
uneven sharing of electrons in a covalent bond.
the interaction between an ion and a non-ionic atom.
an attraction of opposite charges.
equal sharing of valence electrons.
None of the other answer options is correct - Answers uneven sharing of electrons in a covalent
bond.
A woman's doctor tells her to gargle with salt water. She stirs a tablespoon of salt into a cup of
warm water and watches it dissolve. Why does the salt dissolve in water?
The positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative
oxygen atoms in water molecules are attracted to sodium ions.
The negative oxygen atoms in water molecules are attracted to chlorine ions.
The positive hydrogen atoms in water molecules are attracted to chlorine ions.
The negative oxygen atoms in water molecules are attracted to sodium ions.
The positive hydrogen atoms in water molecules are attracted to sodium ions. - Answers The
positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative
oxygen atoms in water molecules are attracted to sodium ions.
A molecule of common table salt, or NaCl, is the result of _____ bond forming between a sodium
(Na) atom and a chlorine (Cl) atom.
an ionic
a polar covalent
a covalent
, a hydrogen
either an ionic or a polar covalent - Answers an ionic
The structural formula for hydrogen gas (H2) is represented as H―H. Here, the dash (―)
represents a(n):
reactant.
product.
electronegative bond.
chemical bond.
chemical reaction. - Answers chemical bond
Water is able to dissolve many compounds as a result of which of the following?
the fact that most nonwater molecules are hydrophobic
the fact that water molecules are polar, and that the hydrogen atoms in water molecules have a
slight negative charge
the fact that water molecules are polar
the fact that the hydrogen atoms in water molecules have a slight negative charge
the fact that water molecules are nonpolar - Answers the fact that water molecules are polar
Which of the following statements is TRUE regarding a polar molecule?
A polar molecule will not dissolve in water.
A polar molecule is hydrophobic.
A polar molecule is hydrophilic and it will dissolve in water.
A polar molecule is hydrophilic.
A polar molecule will dissolve in water. - Answers A polar molecule is hydrophilic and it will
dissolve in water.
The unique properties of water are due to the _____ of water molecules and the ability of water
Which of the following CORRECTLY pairs the particles of an atom with their physical properties?
proton-positively charged; neutron-uncharged; electron-negatively charged
proton-negatively charged; neutron-uncharged; electron-positively charged
proton-positively charged; neutron-negatively charged; electron-uncharged
proton-uncharged; neutron-negatively charged; electron-positively charged - Answers proton-
positively charged; neutron-uncharged; electron-negatively charged
For an atom that is NOT an ion, which of the following must be TRUE?
The number of electrons equals the number of neutrons.
The number of protons equals the number of neutrons.
The number of electrons equals the number of protons. - Answers The number of electrons
equals the number of protons.
Sometimes, atoms gain or lose particles. The loss of which of the following would result in a
change of overall electrical charge?
protons only
neutrons only
electrons only
protons or electrons
protons or neutrons
neutrons or electrons - Answers protons or electrons
Sometimes, atoms gain or lose particles. The loss of which of the following results in a change
of atomic mass?
a neutron and a proton
a neutron
,an electron
a proton
a proton and an electron - Answers a neutron and a proton
A polar bond is due to:
uneven sharing of electrons in a covalent bond.
the interaction between an ion and a non-ionic atom.
an attraction of opposite charges.
equal sharing of valence electrons.
None of the other answer options is correct - Answers uneven sharing of electrons in a covalent
bond.
A woman's doctor tells her to gargle with salt water. She stirs a tablespoon of salt into a cup of
warm water and watches it dissolve. Why does the salt dissolve in water?
The positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative
oxygen atoms in water molecules are attracted to sodium ions.
The negative oxygen atoms in water molecules are attracted to chlorine ions.
The positive hydrogen atoms in water molecules are attracted to chlorine ions.
The negative oxygen atoms in water molecules are attracted to sodium ions.
The positive hydrogen atoms in water molecules are attracted to sodium ions. - Answers The
positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative
oxygen atoms in water molecules are attracted to sodium ions.
A molecule of common table salt, or NaCl, is the result of _____ bond forming between a sodium
(Na) atom and a chlorine (Cl) atom.
an ionic
a polar covalent
a covalent
, a hydrogen
either an ionic or a polar covalent - Answers an ionic
The structural formula for hydrogen gas (H2) is represented as H―H. Here, the dash (―)
represents a(n):
reactant.
product.
electronegative bond.
chemical bond.
chemical reaction. - Answers chemical bond
Water is able to dissolve many compounds as a result of which of the following?
the fact that most nonwater molecules are hydrophobic
the fact that water molecules are polar, and that the hydrogen atoms in water molecules have a
slight negative charge
the fact that water molecules are polar
the fact that the hydrogen atoms in water molecules have a slight negative charge
the fact that water molecules are nonpolar - Answers the fact that water molecules are polar
Which of the following statements is TRUE regarding a polar molecule?
A polar molecule will not dissolve in water.
A polar molecule is hydrophobic.
A polar molecule is hydrophilic and it will dissolve in water.
A polar molecule is hydrophilic.
A polar molecule will dissolve in water. - Answers A polar molecule is hydrophilic and it will
dissolve in water.
The unique properties of water are due to the _____ of water molecules and the ability of water
