CH 2 MB Q's

the root phob means

fear

Root: prot/proto

first

root: de-

from, out of, remove

The root lip/o means

lipid (fat)

The root "phil" means

love

A(n) _____ refers to two or more atoms held together by covalent bonds.

molecule

Root: neutr-

of neither gender or type

An ionic bond is formed when _____.

one atom transfers an electron to another atom

Compared with 31P, the radioactive isotope 32P has

one more neutron

Root: -lysis

split

The reactivity of an atom arises from A. the existence of unpaired electrons in the valence shell. B. the sum of the potential energies of all the electron shells. C. the potential energy of the valence shell. D. the average distance of the outermost electron shell from the nucleus.

the existence of unpaired electrons in the valence shell

Root: Ad

to, toward, near

Root: hydro, hydr

water

What can happen to an electron when sunlight hits it? Select all that apply. 1. It can stay in its original shell. 2. It can collide with the nucleus. 3. It can drop down to a lower electron shell. 4. It can move out to a higher electron shell.

1. It can stay in its original shell. 4. It can move out to a higher electron shell.

What is the mass number of an ion with 108 electrons, 159 neutrons, and a +1 charge?

268

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

6

What does the term electron orbital describe? A. An electron orbital describes a three-dimensional space where an electron can be found 90% of the time. B. An electron orbital describes the orbit of an electron around the nucleus. C. An electron orbital describes the exact distance of an electron from the nucleus. Submit

A. An electron orbital describes a three-dimensional space where an electron can be found 90% of the time. We cannot know the exact location of an electron. Instead, we can describe a three-dimensional space in which an electron spends most of its time.

Use your knowledge of electronegativity to pick out the most polar bond in the list below. A. O-H B. N-H C. O-C D. C-H E. O-N

A. O-H

Chemists assign atoms to chemical elements by counting their ________. A. protons B. electrons C. isotopes D. neutrons

A. Protons Elements are defined by the number of protons. Protons give an enduring basis for atomic behavior because they are permanently anchored in the nucleus, where their attraction determines how many electrons the atom can hold. By contrast, electrons come and go, and the numbers vary. Isotopes of the same element vary in the number of neutrons in the nucleus of the atom.

Which statement is true of all atoms that are anions? A. The atom has more electrons than protons. B. The atom has more neutrons than protons. C. The atom has fewer protons than does a neutral atom of the same element. D. The atom has more protons than electrons.

A. The atom has more electrons than protons.

Which of these relationships is true of an uncharged atom? A. The number of protons is equal to the number of electrons. B. The atomic mass is equal to the number of electrons. C. The number of neutrons is equal to the number of protons. D. The number of electrons is equal to the number of neutrons. E. The atomic mass is equal to the atomic number.

A. The number of protons is equal to the number of electrons.

Radioactive decay is likely to occur when ... A. an atom has too many neutrons. B. an electron hits the nucleus. C. protons break into neutrons and electrons. D. atoms collide with one another. E. an atom has too many electrons.

A. an atom has too many neutrons. The atomic nucleus becomes unstable if the ratio of protons to neutrons is too far from unity.

A carbon atom and a hydrogen atom form what type of bond in a molecule? A. nonpolar covalent bond B. Van der Waals interaction C. ionic bond D.hydrogen bond E. polar covalent bond

A. nonpolar covalent bond Atoms with similar electronegativities form nonpolar covalent bonds.

An ionic bond is formed when __________. A. one atom transfers an electron to another atom B. atoms are subjected to radioactive isotopes C. both atoms are electrically neutral D. both atoms are equally attractive to electrons E. both atoms are nonpolar

A. one atom transfers an electron to another atom

Dr. Jones says an atom has 3 electrons in the first shell and four electrons in the second shell. Someone should tell Dr. Jones that ... A. the first shell shouldn't have 3 electrons. B. no shell can hold more than 2 electrons. C. the first shell must fill before the second shell can have electrons. D. the second shell can't have 4 electrons. E. the second shell should have 8 electrons.

A. the first shell shouldn't have 3 electrons.

An atom has 8 protons, 8 neutrons, and 8 electrons. Another isotope of the same element might have ... A. 7 electrons. B. 10 neutrons. C. mass number 16, atomic number 7. D. 9 protons. E. All of the above

B. 10 neutrons. explanation: Isotopes have the same number of protons; different numbers of neutrons.

The mass number of an atom is 15, and its atomic number is 7. The atom probably has. A. 7 units of negative charge in the nucleus. B. 8 neutrons in the nucleus. C. at least 15 electrons. D. about as much mass in electrons as in protons. E. 7 electrons in the nucleus.

B. 8 neutrons in the nucleus. mass #= p + n = 15 atom #= p = 7 n= 15-7= 8

Which statement is true of atoms? A. Protons repel electrons. B. Electrons determine the atom's size. C. Most of an atom's volume is filled with matter. D. Protons attract other protons E. All of the above

B. Electrons determine the atom's size. explanation: With electrons on the surface, atoms repel one another when they come too close. Thus, electrons determine the space that an atom occupies.

Which of the following is a true statement about how living organisms use energy and chemicals to carry out life's activities? A. Energy cycles within an ecosystem, but chemicals flow through it. B. Energy flows through an ecosystem, but chemicals cycle within it. C. Both energy and chemicals cycle within an ecosystem. D. Both energy and chemicals flow through an ecosystem.

B. Energy flows through an ecosystem, but chemicals cycle within it. Energy flows through an ecosystem in one direction, usually entering as light and exiting as heat. In contrast, chemicals cycle within an ecosystem, where they are used and then recycled.

Which model most accurately represents the current view of the structure of the atom? A. Planetary model B. Probability model

B. Probability model We cannot determine the exact motion of electrons. We can only compute the regions where electrons occur most of the time. To emphasize the uncertainty, a diagram showing random motion is more suitable than planetary paths.

Which statement is true of the energy levels of electrons in shells? A. All the electrons in an atom have similar amounts of energy. B. The valence shell has higher energy than other occupied shells. C. Electrons must lose energy to move from the first to the second shell. D. All of the above E. Non of the above

B. The valence shell has higher energy than other occupied shells. explanation: The outer occupied shell is the valence shell, and outer shells hold electrons at higher energy than inner shells.

Atoms with the same number of protons but with different electrical charges _____. A. have different numbers of neutrons B. are different ions C. have different atomic numbers D. are different isotopes E. have different atomic masses

B. are different ions

Which of the following lists some of the levels of biological organization from less complex to more complex? A. atoms, molecules, organs, cells B. atoms, molecules, cells, organs C. atoms, cells, molecules, organs D. molecules, atoms, cells, organs Submit

B. atoms, molecules, cells, organs

What determines the types of chemical reactions that an atom participates in? A. its atomic mass B. the number of electrons in the outermost electron shell C. the number of protons it contains D. its atomic number E. the number of electrons in the innermost electron shell

B. the number of electrons in the outermost electron shell

What happens when two atoms form a chemical bond? A. Two atoms fuse together to form a chemical bond B. A chemical bond forms when two atoms transfer or share protons to achieve a stable nucleus C. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.

C. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.

What happens when two atoms form a chemical bond? A. Two atoms fuse together to form a chemical bond. B. A chemical bond forms when two atoms transfer or share protons to achieve a stable nucleus. C. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.

C. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells. Only the electrons of atoms participate in chemical bonds, which form when atoms transfer or share outer or valence electrons.

Electrons are held in an atom by attraction to what particle or location? A. Attraction to the other electrons in the atom B. Attraction to the lowest electron shell C. Attraction to the positively charged protons in the nucleus D. Attraction to the magnetic neutrons in the nucleus

C. Attraction to the positively charged protons in the nucleus

An atom has 6 electrons, 6 protons, and 6 neutrons. You can tell that this atom belongs to the element _____ because _____________________. A. N; it has 6 protons. B. O; its mass number is 12. C. C; it has 6 protons. D. C; it has 6 electrons. E. N; it has 6 electrons.

C. C; it has 6 protons. p+n= 12--> C

Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say ... A. No, both bonds are highly polar. B. Yes. O attracts electrons more strongly than C. C. Wrong again, Ralph. Both bonds are nonpolar. D. No way. C is more electronegative than O. E. Right! O is electronegative, so O2 is polar.

C. Wrong again, Ralph. Both bonds are nonpolar. When two atoms of the same kind form a covalent bond, they share electrons equally because their electronegativity is the same.

An ionic bond involves _____. A. the sharing of a single pair of electrons B. the unequal sharing of an electron pair C. an attraction between ions of opposite charge D. no atoms other than sodium and chlorine E. water avoidance

C. an attraction between ions of opposite charge

The atoms of different phosphorus isotopes _____. See Concept 2.2 (Page) A. have different atomic numbers B. have different numbers of protons C. have different numbers of neutrons D. have different numbers of electrons E. react differently with other atoms

C. have different numbers of neutrons The phosphorus atom is defined by its proton number. Changes in neutron number alter the mass of the atom, but not its chemical behavior or reactivity.

The brackets are indicating a(n) _____ bond. A. polar covalent B. single (nonpolar) covalent C. hydrogen D. ionic E. hydrophobic

C. hydrogen

What name is given to the bond between water molecules? A. ionic B. single (nonpolar) covalent C. hydrogen D. hydrophobic E. polar covalent

C. hydrogen

In salt, what is the nature of the bond between sodium and chlorine? A. nonpolar covalent B. hydrophobic C. ionic D. polar covalent E. hydrogen

C. ionic

Which of the following subatomic particles always has a positive charge? A. electron B. atom C. proton D. neutron E. element

C. proton

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

C. protons in an atom

What type of bond joins the carbon atom to each of the hydrogen atoms? A. hydrogen B. double (nonpolar) covalent C. single (nonpolar) covalent D. polar covalent E. ionic

C. single (nonpolar) covalent Each carbon-hydrogen bond involves a single pair of equally shared electrons.

Hydrogen bonding is most often seen __________. A. when the molecule's three-dimensional shape is tetrahedral B. if the molecule consists of three or fewer atoms C. when hydrogen is covalently bonded to an electronegative atom D. when the bonds within the molecule are nonpolar covalent bonds E. when multiple carbon atoms are present

C. when hydrogen is covalently bonded to an electronegative atom

A. An electron will move from the outer to the inner shell. B. The atom has more than one valence electron. C. The atom is in the excited state. D. All of the above. E. Non of the above

D. All of the above explanation The atom has a vacancy in its inner shell; an electron has moved to the outer (valence) shell. The result is an unstable excited state. An electron will move back to the inner shell, restoring the ground state as the atom gives off energy.

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) __________. A. Molecule B. Proton C. Compound D. Element E. Isotope

D. Element

Which the following statements about Darwin's theory of natural selection is true? A. In order to reproduce more successfully, an individual must evolve so that it adapts to its environment. B. Natural selection, by its cumulative effects over long periods of time, could have caused random changes in ancestral species, thus giving rise to two or more descendant species. C. The natural environment consistently causes variation of certain traits in the population. D. Individuals with inherited traits that are better suited to the local environment are more likely to survive and reproduce than less well-suited individuals.

D. Individuals with inherited traits that are better suited to the local environment are more likely to survive and reproduce than less well-suited individuals.

Which of the following statements correctly describes any chemical reaction that has reached equilibrium? A. The reaction is now irreversible. B. The concentrations of products and reactants are equal. C. Both forward and reverse reactions have halted. D. The rates of the forward and reverse reactions are equal.

D. The rates of the forward and reverse reactions are equal.

Which of these refers to atoms with the same atomic number but different atomic masses? A. These atoms are different elements. B. These atoms have different numbers of electrons. C. These atoms are isomers. D. These atoms are isotopes. E. These atoms have different numbers of protons.

D. These atoms are isotopes.

A phrase that applies to covalent bonding and not other kinds of bonds is A. charge attraction B. great strength C. paired electrons D. electron-sharing E. All of the above.

D. electron-sharing

Which of the following is a trace element found in the human body? A. hydrogen B. nitrogen C. carbon D. magnesium E. oxygen

D. magnesium

In the term trace element, the adjective trace means that A. the element is very rare on Earth. B. the element enhances health but is not essential for the organism's long-term survival. C. the element can be used as a label to trace atoms through an organism's metabolism. D. the element is required in very small amounts.

D. the element is required in very small amounts.

Chemical equilibrium is reached when _____. See Concept 2.4 (Page) A. the reverse reaction begins to occur B. matter is conserved C. all of the reactants are converted to products D. the forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same E. the rate at which matter is destroyed and the rate at which it is created offset each other

D. the forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same

Two atoms always represent the same element if they have ... A. the same mass number. B. the same number of shells. C. the same number of electrons. D. the same number of protons. E. the same number of particles in the nucleus.

D. the same number of protons.

If you want a molecule that is highly polar, look for one that contains: A. C-S B. C-H C. O-N D. S-H E. H-N

E. H-N

Which atom in the pictured molecule will have the strongest partial positive charge? A. The O atom that's in C=O. B. The H that's bound to O. C. The N atom. D. The C that's bound to N. E. The C that's in C=O.

E. The C that's in C=O. This C atom is bound to the two most electronegative atoms in the molecule (O), both of which are pulling electrons from C.

The type of bonding and the number of covalent bonds an atom can form with other atoms is determined by __________. A. the number of protons B. the nucleus C. the number of neutrons D. the size of the atom: smaller atoms are chemically more reactive E. the number of unpaired electrons in the valence shell

E. the number of unpaired electrons in the valence shell

Which answer correctly ranks the atoms in terms of decreasing electronegativity (the highest electronegativity first)? O, N, H, C O, N, C, H N, O, C, H N, O, H, C C, H, O, N

O, N, C, H