AP Chemistry Units 1 & 2 Multiple Choice Review

Based on the Lewis diagram for NH3, shown above, the H-N-H bond angle is closest to which of the following?

109.5

The elements C and Se have the same electronegativity value, 2.55. Which of the following claims about the compound that forms from C and Se is most likely to be true?

A molecule of the compound will have a partial negative charge on the carbon atom.

Which ion listed has no resonance structures and exactly two pi bonds

CN-

Rb reacts with O in a mole ratio of 2 to 1, forming the ionic compound Rb2O. Which of the following elements will react with O in a mole ratio of 2 to 1, forming an ionic compound, and why?

Cs , because it is in the same group as Rb.

Which of the following scientific claims about the bond in the molecular compound HF is most likely to be true?

It's highly polar.

A jar labeled NaCl contains a powder. The table above contains information determined by analyzing a sample of the powder in the laboratory. What information in the table is the most helpful in determining whether the powder is pure NaCl?

Mass percent of Na

Which pair of elements is likely to produce a nearly nonpolar covalent bond

N and F

Which of the following claims about a binary compound composed of elements with the same electronegativity is most likely to be true?

The compound has properties similar to those of both elements.

What best explains the following trend: Melting point order: LiF > NaCl > KBr > Csl

The greater radii of the larger ions result in smaller lattice energies, leading to lower melting points

In a lab a student is given a 21g sample of pure Cu metal. Which of the following pieces of information is most useful for determining the number of Cu atoms in the sample? Assume that the pressure and temperature in the lab are 1.0atm and 25°C.

The molar mass of Cu

The atomic radii of the elements in the nitrogen group in the periodic table are given in the table above. Which of the following best helps explain the trend of increasing atomic radius from N to Bi?

The number of electrons in the outermost shell of the atom increases.

Which of the following best helps explain why the first ionization energy of K is less than that of Ca?

The valence electron of K experiences a lower effective nuclear charge than the valence electrons of Ca .

Which of the following best explains the difference in the melting points of MgO (2852C) ans NaF (1819C)

There are greater Coulombic attractions in McO due to the greater charges on the ions

Which of the following claims about a binary compound in which the bonding is ionic is most likely to be scientifically valid?

There is equal sharing of electrons between the atoms of the elements in the compound.

Which of the following best describes BF3 and NF3

They have different geometry and different shapes

A 42.0g sample of compound containing only C and H was analyzed. The results showed that the sample contained 36.0g of C and 6.0g of H. Which of the following questions about the compound can be answered using the results of the analysis?

What is the empirical formula of the compound?

A student measures the mass of a sample of a metallic element, M. Then the student heats the sample in air, where it completely reacts to form the compound MO. The student measures the mass of the compound that was formed. Which of the following questions can be answered from the results of the experiment?

What is the molar mass of M ?

In a molecule in which the central atom exhibits sp2 orbitals, the arrangement of electron pairs is

trigonal planar