Chapter 11

Element X, which has a valence shell configuration of $\mathrm{n}{s}^2\mathrm{n}{p}^4,$ was isolated in a laboratory. Which of the following statements is(are) true concerning element X? a. Element X has chemical properties similar to those of the halogens. b. Element X has six valence electrons. c. When element $X$ is reacted with calcium, the compound formed would most likely have the formula ${\mathrm{Ca}}_2\mathrm{X}$. d. Element X needs to gain two electrons to attain a noble gas electron configuration.

Why do we believe that the three electrons in the $2p$ sublevel of nitrogen occupy different orbitals?

Write the full electron configuration $(1s^{2}2s^2,$ etc. $)$ for each of the following elements. a. bromine, $Z=35$ b. xenon, $Z=54$ c. barium, $Z=56$ d. selenium, $Z=34$

What name is given to the series of ten elements in which the electrons are filling the $3d$ sublevel?

Rank the following elements in order of increasing atomic size: Ge, $\mathrm{S},\mathrm{F},\mathrm{Rb},\mathrm{Mn}$

Arrange the following atoms in order of increasing size (assuming all atoms are in their ground states). a. $[\mathrm{Kr}]5s^{2}4d^{10}5p^6$ b. $[\mathrm{Kr}]5s^{2}4d^{10}5p^1$ c. $[\mathrm{Kr}]5s^{2}4d^{10}5p^3$

Write the shorthand valence shell electron configuration of each of the following elements, basing your answer on the element's location on the periodic table. a. nickel, $Z=28$ b. niobium, $Z=41$ c. hafnium, $Z=72$ d. astatine, $Z=85$

Which of the following statements about the periodic table is false? a. Elements in the same column have similar reactivities because their valence electrons tend to be located in the same types of orbitals. b. A series of ions that are isoelectronic (contain the same number of electrons) in their ground states must have the same electron configuration. c. The atomic size of the elements increases going across a period from left to right because the number of electrons increases, so the electrons are located further from the nucleus. d. It takes more energy to remove an electron from lithium than from cesium because the valence electrons in lithium are located closer to the nucleus.

In each of the following sets of elements, indicate which element shows the most active chemical behavior. a. $\mathbf{B},\mathbf{A}\mathbf{l},\mathbf{I}\mathbf{n}$ b. $\mathrm{Na},\mathrm{Al},\mathrm{S}$ $\mathrm{c}\cdot \mathrm{B},\mathrm{C},\mathrm{F}$

In each of the following sets of elements, indicate which element has the smallest atomic size. a. $\mathrm{Ba},\mathrm{Ca},\mathrm{Ra}$ b. $P,Si,Al$ $\mathrm{c}.\mathrm{Rb},\mathrm{Cs},\mathrm{K}$