Give a reason why each of the following statements is a safe prediction: (a) Every compound of Rb with a nonmetal is ionic in character. (b) Every compound of nitrogen with a halogen element is a molecular compound. (c) The compound MgKr2 does not exist. (d) Na and K are very similar in the compounds they form with nonmetals. (e) If contained in an ionic compound, calcium (Ca) will be in the form of the doubly charged ion, Ca2+.

See explanation

Explanation:

a) An ionic bond is a bond that is created by the electrostatic attraction between a negative and a positively charged ion. Binding is only possible between atoms with a large difference in electronegativity. These are bonds between atoms with a metal character and atoms with a non-metal character. Rb is a positive charged metal. Together with a non-metal it will make an ionic bond, because the electronegativity is big enough.

b) Nitrogen is a diatomic molecule in the VA family on the periodic table. Nitrogen has five valence electrons, so it needs three more valence electrons to complete its octet. A nitrogen atom can fill its octet by sharing three electrons with another nitrogen atom, forming three covalent bonds, a so-called triple bond.

Covalent bonds are chemical bonds in which two or more elements join together by sharing electrons, rather than transferring electrons, as is the case with ionic bonds ... These elements are considered to be covalent. Other elements that can form covalent bonds include nitrogen, carbon and fluorine.

c) MgKr2 does not exist because magnesium (Mg2+) has 2 valence electrons. This means it will bind with 2 atoms with 7 valence electron (like Cl - and form Mgcl2) or with 1 atom with 6 valence electrons (like oxygen and form MgO). This to form a stable noble gas configuration. Since Kr is a noble gas it already has 8 valence electrons and is already stable, so 2 Kr atoms cannot bind on Magnesium. MgKr2 does not exist.

d) Na and K are both part of the alkali group, this means they have only 1 valence electron. Since the most non-metals have 6 or 7 valence electrons, they will bind on the same way. Both are also part of the s-block.

e) Calcium is a positive charged metal. IT will bind to a negative charged non-metal to form an ion bond. Calcium is in group 2, so it has 2 valence electrons. This means it will appear as Ca2+.

An example CaBr2. Br has 7 valence electrons. So 2 Br atoms will bind on Calcium since it's in its form Ca2+, where are 2 valence electrons.