BIO 150 LECTURE Ch 2

A sodium atom has a mass number of 23. Its atomic number is 11. How many electrons does it have (if it is not an ion)? A. 11 B. 12 C. 22 D. 23 E. 34

A. 11

How many neutrons does the nucleus of sulfur contain? Atomic Mass 12 16 1 14 32 31 Symbol C O H N S P Atomic # 6 8 1 7 1 6 15 A. 16 B. 19 C. 32 D. 35 E. 51

A. 16

How many electrons does carbon have in its outermost (valence) energy level? Atomic Mass 12 16 1 14 32 31 Symbol C O H N S P Atomic # 6 8 1 7 1 6 15 A. 4 B. 8 C. 7 D. 5 E. 2

A. 4

The ionic bond of sodium chloride is formed when A. chlorine gains an electron from sodium. B. sodium and chlorine share an electron pair. C. sodium and chlorine both lose electrons from their outer energy levels. D. sodium gains an electron from chlorine. E. chlorine gains a proton from sodium.

A. chlorine gains an electron from sodium

atomic forms of an element containing different numbers of neutrons are A. isotopes. B. ions. C. polar atoms. D. isomers. E. metals.

A. isotopes

. Electrons are shared equally in a(n) ______________bond. A. nonpolar covalent B. hydrogen C. ionic D. polar covalent E. electronic

A. nonpolar covalent

Would be least affected by the presence of water A. nonpolar covalent bond B. polar covalent bond C. ionic bond D. hydrogen bond E. hydrophobic interaction

A. nonpolar covalent bond E. hydrophobic interaction

A covalent bond is likely to be polar when A. one of the atoms sharing electrons is much more electronegative than the other atom. B. the two atoms sharing electrons are equally electronegative. C. the two atoms sharing electrons are of the same element. D. it is between two atoms that are both very strong electron acceptors. E. the two atoms sharing electrons are different elements

A. one of the atoms sharing electrons is much more electronegative than the other atom.

The mass number of an element can be easily approximated by adding together the number of A. protons and neutrons. B. electron orbitals in each energy level. C. protons and electrons. D. neutrons and electrons. E. isotopes of the atom.

A. protons and neutrons

What is the maximum number of covalent bonds an element with atomic number 16 can make with hydrogen? A. 1 B. 2 C. 3 D. 4 E. 5

B. 2

Polar substances are ___________; nonpolar substance are __________ A. hydrophilic; also hydrophilic. B. Hydrophilic; hydrophobic. C. Hydrophobic,alsohydrophobic. D. Hydrophobic ; hydrophilic. E. Polar ; nonpolar.

B. Hydrophilic; hydrophobic.

Each element is unique and different from other elements because of its A. atomic weight. B. atomic number. C. mass number. D. Only A and B are correct. E. A, B, and C are correct.

B. atomic number.

When the proton number and electron number are unequal, the atom or molecule A. forms a covalent bond with another atom. B. gains or loses an electron. C. becomes part of a molecule. D. gains or loses a proton. E. gains or loses a neutron.

B. gains or loses an electron.

Atoms of different phosphorus isotopes A. have different atomic numbers. B. have different numbers of neutrons. C. react differently with other atoms. D. have different numbers of electrons. E. have different numbers of protons.

B. have different numbers of neutrons.

Results from an unequal sharing of electrons between atoms. A. nonpolar covalent bond B. polar covalent bond C. ionic bond D. hydrogen bond E. hydrophobic interaction

B. polar covalent bond

Which atom is most likely to become a cation? A. argon B. sodium C. oxygen D. chlorine E. phosphorus

B. sodium

Which of the following statements are correctly describes any chemical reaction that has reached equillibrum? A. The concentterm-49ration of products equals the concentration of reactants. B. the rate of forward reaction equals the rate of reverse reaction. C. Both forward and reverse reactions have halted. D. None of the reactants is present. E. None of the products is present.

B. the rate of forward reaction equals the rate of reverse reaction.

The biological function of a molecule is most directly related to A. the number of atoms which form the molecule. B. the shape of the molecule. C. the number of valence electrons present among the atoms. D. whether the molecule's bonds are covalent or ionic. 5 E. whether the valence shell orbitals hybridize during covalent bonding.

B. the shape of the molecule.

Results from a transfer of electrons between atoms A. nonpolar covalent bond B. polar covalent bond C. ionic bond D. hydrogen bond E. hydrophobic interaction

C ionic bond

One difference between carbon 12 and carbon 14 is that carbon 14 has A. 2 more protons than carbon 12. B. 2 more electrons than carbon 12. C. 2 more neutrons than carbon 12. D. Only A and C are correct. E. A, B, and C are correct.

C. 2 more neutrons than carbon 12.

How many electrons would be expected in the outer energy level of an atom with atomic number 17? A. 2 B. 5 C. 7 D. 8 E. 17

C. 7

Which of the following represents a polar covalent bond? A. H-H B. C-C C. H-O D. C-H E. O-O

C. H-O

Which of the following best describes the relationship between the atoms described below? atom 1 atom 2 1 3 H H 1 1 A. They are isomers. B. They are polymers. C. They are isotopes. D. They are ions. E. They are both radioactive.

C. They are isotopes.

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 particularly stable and nonreactive. D. be particularly unstable and very reactive. E. be biologically important since they are present in organic molecules.

C. be particularly stable and nonreactive

Which of the following is a trace element that is essential to humans? A. nitrogen. B. calcium C. iodine D. carbon E. oxygen

C. iodine

What bond(s) is (are) easily disrupted in the presence of water? A. covalent B. polar covalent C. ionic D. Only A and B are correct. E. A, B, and C are correct.

C. ionic

How do isotopes differ from each other? A. number of protons B. number of electrons C. number of neutrons D. valence electron distribution E. ability to form ions

C. number of neutrons

A covalent chemical bond is one in which A. electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B. protons or neutrons are shared by two atoms so as to satisfy the requirements of both. C. outer shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both. D. outer shell electrons of one atom are transferred to the inner electron shells of another atom. E. the inner shell electrons of one atom are transferred to the outer shell of another atom.

C. outer shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both.

Which of the following is the smallest in volume? A. nucleus of an oxygen atom B. water molecule C. proton D. ice crystal E. electron cloud of an oxygen atom

C. proton

Changing the number of _____ would change an atom into an atom of a different element. A. bonds formed by an atom B. electrons circling the nucleus of an atom C. protons in an atom D. particles in the nucleus of an atom E. neutrons in an atom

C. protons in an atom

Which of the following holds atoms together in a molecule? A. transfer of electron from one atom to another B. transfer of protons from one atom to another C. sharing of electrons between atoms D. loss of neutrons by atoms E. sharing of protons between atoms

C. sharing of electrons between atoms

The atomic number of neon is 10. Therefore it A. has 8 electrons in the outer electron shell. B. is inert. C. has an atomic mass of 10. D. Only A and B are correct. E. A, B, and C are correct.

D. Only A and B are correct

Oxygen has an atomic number of 8. Therefore, it must have A. 8 protons. B. 8 electrons. C. 8 neutrons. D. Only A and B are correct. E. A, B, and C are correct

D. Only A and B are correct.

From its atomic number of 15, it is possible to predict that the phosphorus atom has A.15 neutrons. B. 15 protons. C. 15 electrons. D. Only B and C are correct. E. A, B, and C are correct.

D. Only B and C are correct

Based on electron configuration, which of these elements would exhibit chemical behavior most like that of oxygen? Atomic Mass 12 16 1 14 32 31 Symbol C O H N S P Atomic # 6 8 1 7 1 6 15 A. C B. H C. N D. S E. P

D. S

An _________has a net charge of zero; an ___________has gained or lost one or more electrons, and so has negatively or positively charged. A. ion; ion B. atom; atom C. ion; atom D. atom; ion E. atom; molecule

D. atom; ion

The reactive properties of an atom depend on the number of A. valence shells in the atom. B. orbitals found in the atom. C. electrons in each orbital in the atom. D. electrons in the outer valence shell in the atom. E. hybridized orbitals in the atom.

D. electrons in the outer valence shell in the atom.

When two atoms are equally electronegative, they will interact to form A. equal numbers of isotopes. B. ions. C. polar covalent bonds. D. nonpolar covalent bonds. E. ionic bonds.

D. nonpolar covalent bonds

Fluorine atoms tend to take electrons from any atoms that come near. As a result, fluorine atoms A. tend to become positively charged. B. are nonpolar. C. do not react readily with other atoms. D. tend to form ionic bonds. E. are not very electronegative.

D. tend to form ionic bonds

The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon? A. 7: nitrogen B. 9: fluorine C. 10: neon D. 12: magnesium E. 14: silicon

E. 14: silicon

An atom that normally has _____ in its outer shell would tend not to form chemical bonds with other atoms. A. 1 electron B. 3 electrons C. 4 electrons D. 6 electrons E. 8 electrons

E. 8 electrons

Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is CORRECT about ammonia (NH3)? A. Each hydrogen atom has a partial positive charge. B. The nitrogen atom has a partial negative charge. C. Each hydrogen atom has a slight negative charge. D. The nitrogen atom has a partial positive charge. E. Both A and B

E. Both A and B A. Each hydrogen atom has a partial positive charge. B. The nitrogen atom has a partial negative charge.

What are the chemical properties of atoms whose valence shells are filled? A. They form ionic bonds in aqueous solutions. B. They form covalent bonds in aqueous solutions. C. They are particularly stable and unreactive. D. They exhibit similar chemical behaviors. E. Both C and D are correct.

E. Both C and D are correct.

How an atom behaves when it comes into contact with other atoms is determined by its A. nucleus. B. size. C. protons. D. neutrons. E. electrons.

E. electrons.

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 shell

They all have unpaired electrons in their valence shell

Which four elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

Which of the following is not considered a weak molecular interaction? A. covalent bond B. ionic bond in presence of water C. hydrogen bond D. Van der Waal's interaction

covalent bond