1 CHEM 101 WRITTEN EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+ In general, covalent bonding can occur between which of the following? Correct Answer: Two neutral atoms Different ions of a given element will have differing numbers of __________. Correct Answer: electrons Manganese oxide is formed from Mn5+ cations and O2− anions. What will be its chemical formula? Correct Answer: Mn2O5 An ionic compound must be electrically neutral, so it must have the same number of positive and negative charges. Two manganese cations, each with a charge of 5+, would give us ten positive charges, while five oxygen anions, each with a charge of 2−, would give us ten negative charges. Therefore, the formula would be Mn2O5. Which of the following is a molecular compound? HF NaF 2 CaCl2 MgO Correct Answer: HF is a compound consisting of two nonmetals, which will form a covalent bond. Molecular compounds are composed of covalently bonded nonmetals. What is a cation? Correct Answer: an atom that has lost electrons Mg3N2 consists of __________. Correct Answer: Mg2+ and N3− ions From the periodic table, we know that magnesium will form 2+ ions, and nitrogen will form 3− ions. The two will, therefore, come together in a 3:2 ratio to form a neutral compound. Which of the following is a molecular compound? Li2CO3 KI H2O2 CaF2 Correct Answer: H2O2, or hydrogen peroxide, consists of covalently bonded nonmetals, and is therefore molecular. 3 Potassium selenide is formed from the K+ cation and the Se2− anion. What is the correct formula for this compound? Correct Answer: K2Se An ionic compound must be electrically neutral, so it must have the same number of positive and negative charges. Two potassium ions, each with a charge of 1+, would give us two positive charges, while one selenide ion, with a charge of 2−, would give us two negative charges. Therefore, the formula is two potassium ions to one selenide ion: K2Se. Neutral nonmetal atoms typically gain electrons, thus becoming __________. Correct Answer: anions Ions may consist of __________. Correct Answer: Ions can be either monoatomic, consisting of one atom, or polyatomic, consisting of multiple atoms. There is no specific limit to the number of atoms in an ion. Neutral atoms that gain electrons become __________. Correct Answer: Neutral atoms that gain electrons become anions (negatively charged ions). Which of the following elements will form a molecular compound with one another?
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