Chapter 7.1

What is the electron configuration of Cl−?

1s22s22p63s23p6 The electron configuration of Cl− would be one more electron than the original configuration of Cl so the answer is [Ne]3s23

The electron configuration of the neutral element arsenic (As) is [Ar]4s23d104p3. Use this information to determine the charge of the arsenide anion.

3- Given the electron configuration of As, we can see how many electrons it would take to make the nearest noble gas configuration, (Kr). Notice that the 4p orbital has 3 electrons in it. It would require 3 more electrons to fill the 4p orbital, which means that the charge on the arsenide ion is 3−. The formula is As3−.

Which is NOT a typical cation of chromium? 2+ 3+ 5+ 6+

5+ Most transition metals will readily form 2+ and 3+ ions. The electron configuration for neutral chromium is 1s22s22p63s23p64s13d5. Chromium is a d-block transition metal, and so the valence electrons are removed from the ssubshell before they are removed from the d subshell. Therefore, Chromium would lose its one s electron first and a delectron to form Cr2+, which is only stable in the absence of air. Chromium can also lose its one s electron and two more delectrons to become Cr3+, which is the most stable oxidation state for chromium. Chromium can also lose all the remaining valence electrons to become Cr6+. Chromium is seen in this oxidation state in chromium(VI) sulfide Cr2S3.

Which of the following has the greatest lattice energy? NaF CsI CaO All have same energy

CaO CsI has a charge of (+1,−1), while NaF is (+1,−1), and CaO is (+2,−2). Lattice energy is directly proportional to charge, so CaO would have the largest value.

______ is the energy required to break apart an ionic solid, and convert its components into gaseous ions.

Lattice energy Lattice energy is a measure of the strength of the attraction between the positive and negative ions in an ionic compound. In other words, the lattice energy is the amount of energy necessary to separate the attracted ions in the ionic compound.

Which of the following is the correct neutral ionic compound when magnesium (Mg) ions and chloride (Cl) ions are combined?

MgCl2 One Mg2+ ion and two Cl− ions will result in MgCl2, a neutral compound.

Which of the following statements about nonmetal anions are true? Select all that apply: Nonmetals tend to form anions by gaining electrons to form a noble gas configuration. Nonmetals do not tend to form anions. Anions of nonmetals tend to be isoelectronic with a noble gas. Nonmetals tend to form anions by losing electrons to form a noble gas configuration.

Nonmetals tend to form anions by gaining electrons to form a noble gas configuration. Anions of nonmetals tend to be isoelectronic with a noble gas. Most monatomic anions form when a neutral nonmetal atom gains enough electrons to completely fill its outer s and porbitals (valence orbitals), thereby reaching the electron configuration of the next noble gas. Anions that have the same number of electrons as the next noble gas makes the anion isoelectronic with the noble gas.

What is the electronic structure of V2+?

Vanadium's electron configuration is 1s22s22p63s23p64s23d3. Vanadium is a d-block transition metal, therefore we remove the two valence electrons from the 4s subshell to form vanadium(II), giving us 1s22s22p63s23p63d3. Alternatively, this can be written using the symbol [Ar] to represent the noble gas core; [Ar]3d3.

When the absolute value of the difference in electronegativity of two adjacent atom in a compound is 1, they are most likely bonded by ________.

a polar covalent bond. When the absolute value of the difference in electronegativity of two bonded atoms is between 0.4 and 1.8, they tend to form polar covalent bonds.

When comparing H2 and HCl, the hydrogen atom in the HCl molecule will:

be surrounded by less electron density A chlorine atom will draw electron density away from the hydrogen atom, so hydrogen will have lost some electron density in the HCl molecule, whereas in a hydrogen molecule, each hydrogen has the same amount of electron density.

When covalent bonds break:

energy is absorbed Energy must be added to break covalent bonds (endothermic), whereas forming covalent bonds releases energy (exothermic).

When covalent bonds form:

energy is released Since the formation of covalent bonds brings the system to a lower energy, that quantity of energy is released from the system when the bonds form, making their formation exothermic.

Ionic compounds tend to form between a nonmetal with ________ and a metal with __________.

high electron affinity, low ionization energy Nonmetals tend to have a high electron affinity whereas metals tend to have low ionization energies. A metal with a low ionization energy can easily lose an electron. A nonmetal with a high electron affinity can easily gain an electron. Thus if these elements come into contact, an electron will transfer from the metal to the nonmetal, forming an ionic compound as a result.

Lattice energy and interionic distance are:

inversely proportional As the interionic distance decreases, the lattice energy increases.

Ionic compounds tend to be:

neutral By definition, ionic compounds are composed of both positive cations and negative anions and bear a neutral overall charge. Therefore, these ions must come together in a particular ratio so as to result in a neutral substance.

The elements in the p block that are least likely to form anions are the:

noble gases With a full valence shell, the noble gases are unlikely to gain any electrons, as it will be highly energetically unfavorable for them to do so.

Lattice energy is defined as the energy required to break the solid into its component ions, or equivalently, the enthalpy change for the following reaction. MX(s)⟶M+(g)+X−(g)ΔH=ΔHlattice According to this definition, lattice energies are always ____________.

positive By convention, the lattice energy is defined as the energy required to break the solid into its component ions. This process can represented for a generic ionic solid that consists of M+ and X− by the following chemical equation. MX(s)⟶M+(g)+X−(g)ΔHlattice>0 This process is always endothermic; therefore, the lattice energies are expressed as positive values.

In a polar covalent bond, the atom that attracts the electrons less strongly has:

the partial positive charge In a polar covalent bond, the atom that attracts the electrons less strongly has the partial positive charge because the other atom holds on more tightly to the negative electrons.

A covalent bond holds two atoms near each other because

the two electrons that form the bond are attracted to both nuclei. When two electrons from two different atoms each feel the attraction of the other atom's nucleus, a covalent bond can form.

What happens to the 1s orbitals on the hydrogen atoms as they approach to make a covalent bond?

they begin to overlap They begin to overlap in a direct or head-on fashion. It is this overlapping of orbitals that allows the electrons to interact with both nuclei.