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Chemistry Mid Term 2

Measurement

Question: The measurement 0.020 L is the same as (formatting note: numbers following a ^ are exponents)
a) 2.0 x 10^–3 L. b) 2.0 x 10^2 L. c) 2.0 x 10^–2 L. d) 2.0 x 10^–1 L.
Answer: 2.0 x 10^–2 L

Question: Which of these measurements has been expressed to three significant figures?
a) 0.052 g b) 0.202 g c) 3.065 g d) 500 g
Answer: 0.202 g

Question: If repeated measurements agree closely but differ widely from the accepted value, these measurements are
a) neither precise nor accurate. b) accurate, but not precise. c) both precise and accurate. d) precise, but not accurate.
Answer: precise, but not accurate

Question: When 5.7 m is divided by 2 s, the quotient is correctly reported as (use the correct number of significant figures)
a) 2.8 m/s. b) 2.85 m/s. c) 2.9 m/s. d) 3 m/s.
Answer: 3 m/s

Question: If 1 inch equals 2.54 cm, how many centimeters equal 1 yard?
a) 0.0706 cm b) 14.2 cm c) 30.5 cm d) 91.4 cm
Answer: 91.4 cm

Atomic Theory

Question: Which of the following statements is true according to modern atomic theory?
a) Atoms of the same element may have different masses. b) Atoms may be divided in ordinary chemical reactions. c) Atoms can never combine with any other atoms. d) Cathode rays are composed of protons..
Answer: Atoms of the same element may have different masses

Question: According to the Bohr model of the atom, the single electron of a hydrogen atom circles the nucleus
a) in specific, allowed orbits. b) in one fixed orbit at all times. c) at any of an infinite number of distances, depending on its energy. d) counterclockwise.
Answer: in specific, allowed orbits

Question: Because most particles fired at metal foil passed straight through, Rutherford concluded that
a) atoms were mostly empty space. b) atoms contained no charged particles. c) electrons formed the nucleus. d) atoms were indivisible.
Answer: atoms were mostly empty space

Question: The nucleus of an atom has all of the following characteristics except that it
a) is positively charged. b) is very dense. c) contains nearly all of the atom's mass. d) contains nearly all of the atom's volume.

Answer: contains nearly all of the atom's volume

Question: Which model of the atom explains the orbitals of electrons as waves?
Answer: the quantum model or quantum theory

Electrons

Question: If an element has an octet of electrons in its highest main energy level, there are ____ electrons in this level.
Answer: eight

Question: As the atomic number increases, the number of electrons in a neutral atom______________.
Answer: increases.

Question: The number of valence electrons in Group 1 elements is ___________.
Answer: one.

Question: The electron notation for aluminum (atomic number 13) is
a) 1s2 2s2 2p3 3s2 3p3 3d1. b) 1s2 2s2 2p6 3s2 2d1. c) 1s2 2s2 2p6 3s2 3p1. d) 1s2 2s2 2p9.

Answer: C) 1s2 2s2 2p6 3s2 3p1

Question: The major difference between a 1s orbital and a 2s orbital is that __________________.

Answer: the 2s orbital is at a higher energy level (or is larger)

Periodic Trends

Question: Elements in a group or column in the periodic table can be expected to have similar
a) atomic masses. b) atomic numbers. c) numbers of neutrons. d) properties
Answer: properties.

Question: What is removed when the ionization energy is supplied to an atom of an element?
a) the electron cloud b) the nucleus c) an electron d) an ion
Answer: an electron

Question: Across a period in the periodic table, atomic radii
a) gradually decrease. b) gradually decrease, then sharply increase. c) gradually increase. d) gradually increase, then sharply decrease.
Answer: gradually decrease

Question: The element that has the greatest electronegativity is
a) oxygen. b) sodium. c) chlorine. d) fluorine.
Answer: fluorine

Question: Which of the following compounds has the greatest atomic radius?
a) lithium b) neon c) boron d) sodium
Answer: sodium

Bonding

Question: A positive ion is known as a(n)
a) ionic radius. b) valence electron. c) cation. d) anion
Answer: cation

Question: The electrons involved in the formation of a chemical bond are called
a) dipoles. b) s electrons. c) Lewis electrons. d) valence electrons.
Answer: valence electrons

Question: In metals, the valence electrons
a) are attached to particular positive ions. b) are shared by all of the atoms. c) are immobile. d) form covalent bonds.
Answer: are shared by all of the atoms

Question: The name of the ionic compound with formula Li2O is
Answer: lithium oxide

Question: The name of the ionic compound with formula SnCl2 is
Answer: tin (II) chloride