$$3.98 \times 10$$^{-19}$$\ \mathrm{J}$$

Question 1

A sample of an unknown metal has a mass of 45.0 g and a volume of 15.0 cm$$^3. $$What is the density of the metal?

Accepted Answer

$$3.0\ \mathrm{g/cm^3$}$$

Question 2

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 3

Which of the following ions is isoelectronic with Ne?

Accepted Answer

$$\mathrm{F^-}$$

Question 4

Which element has the highest first ionization energy?

Accepted Answer

Neon ($$\mathrm{Ne})$$

Question 5

What is the condensed electron configuration for $$\mathrm{Fe$$^{2+}$$}$$?

Accepted Answer

$$[\mathrm{Ar}]\ 3d^6$

Question 6

Which of the following molecules has a trigonal planar molecular geometry according to VSEPR theory?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 7

A photon has a frequency of $$6.0 	imes 10$$^{14}$$\ \mathrm{Hz}. $$What is its energy? ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s})$$

Accepted Answer

$$3.98 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 8

Which of the following compounds is ionic?

Accepted Answer

$$\mathrm{NaCl}$$

Question 9

Which of the following best describes the bond in $$\mathrm{O_2$}$$?

Accepted Answer

A double bond consisting of one sigma and one pi bond

Question 10

Which of the following statements about lattice energy is correct?

Accepted Answer

Lattice energy increases as the charges of the ions increase and the ionic radii decrease.

Question 11

Which of the following molecules is nonpolar, even though it contains polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 12

How many unpaired electrons are present in a ground-state atom of nitrogen ($$\mathrm{N}$$)?

Accepted Answer

3

Question 13

Which of the following is the best Lewis structure for the nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

A structure with three resonance forms, each with a double bond to a different oxygen and formal charges of -1 on one oxygen and 0 on the others.

Question 14

Which of the following atoms has the largest atomic radius?

Accepted Answer

$$\mathrm{K}$$

Question 15

What is the formal charge on the central atom in $$\mathrm{NH_4$^+}$$?

Accepted Answer

0

Question 16

Which of the following best describes the hybridization of the central atom in $$\mathrm{CH_4$}$$?

Accepted Answer

$$sp^3$$

Question 17

Which of the following is a correct condensed electron configuration for $$\mathrm{Br}$$?

Accepted Answer

$$[\mathrm{Ar}]\ 4s^2$\ 3d$$^{10}$$\ 4p^5$

Question 18

Which of the following pairs are isoelectronic?

Accepted Answer

$$\mathrm{Mg$$^{2+}$$}$$ and $$\mathrm{Ne}$$

Question 19

Which of the following best explains why the second ionization energy of sodium is much greater than the first?

Accepted Answer

The second electron is removed from a stable, noble gas configuration.

Question 20

Which of the following molecules has a bond angle closest to $$109.5^\circ$$?

Accepted Answer

$$\mathrm{CH_4$}$$

General Chemistry Core Concepts: Structured Study Notes

Guida di studio - Domande di pratica