On the basis of electronegativity, which of these pairs of elements is most likely to form polyatomic ions?

question 1 options:

o and p

na and br

cs and cl

ba and o
question 2

which of the following pairs of elements would most likely combine to form a salt?

question 2 options:

na and c

cs and i

i and f

n and f
question 3

which of the following substances best conducts electricity in an aqueous solution?

question 3 options:

co 2

ch 3oh

h 2o

kcl
question 4

which of the following rules would apply to the naming of cacl2?

question 4 options:

metal cation + nonmetal anion(–ide)

metal cation + (roman numeral valence) + nonmetal anion(–ide)

metal + polyatomic anion

polyatomic cation + nonmetal anion(–ide)

question 5

a salt forms in the reaction of aluminum with chlorine. what is the most likely formula unit of this salt?

question 5 options:

alcl

alcl 3

alcl 2

al 3cl
question 6
in a lewis diagram for methane (ch 4), which atom or atoms is inside, or central?
question 6 options:

hydrogen

neither, carbon and hydrogen are both inside

carbon

neither, carbon and hydrogen are both outside
question 7
on the basis of bonding, which of the following is true about sodium chloride when compared to sucrose?
question 7 options:

sodium chloride dissolves in water, but sucrose does not.

sodium chloride has a lower melting point than sucrose.

sodium chloride has a higher boiling point than sucrose.

sodium chloride crystals are softer than sucrose crystals.
question 8
which of the following is true about the compound ammonium phosphate [(nh 4) 3po 4]?
question 8 options:

it is a mixture of two monatomic nitrogen and hydrogen ions and one polyatomic phosphate ion.

it is a salt of three polyatomic ammonium ions and one polyatomic phosphate ion.

it is a mixture of three polyatomic ammonium ions and two polyatomic phosphate ions.

it is a salt of monatomic nitrogen, hydrogen, phosphorus, and oxygen ions.
question 9
which of these pairs of elements is most likely to be part of a polyatomic ion?
question 9 options:

k and f

mg and br

l i and i

s and o
question 10
what is the correct name of the compound mn 3(po 4) 2?
question 10 options:

manganese(ii) phosphate

manganese(iii) phosphate

manganese(i) phosphate

manganese phosphate

1) Answer is: O and P.

Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

Oxygen (O) has greater electronegativity than phosphorus (P), because of that oxygen is partially negative and phosporus is partially positive.

Polyatomic ion is for example a molecule that has been ionized by gaining or losing electrons.

Oxygen and phosphorus can form ion PO₄³⁻.

2) Answer is: Cs and I.

Cesium (Cs) and iodine form salt cesium iodide (CsI) with ionic bond.

Ionic bond is the electrostatic attraction between oppositely charged ions (cations and anions).

Cesium (metal) lost one electron and form cation Cs⁺; iodine (nonmetal) gain one electron and form anion I⁻.

3) Answer is: KCl.

Potassium chloride is a salt with ionic bond.

Substances with ionic bond conduct an electric current in liquid and aqueous solutions, but not in solid state, because in liquids ions are mobile, contrary to solids where ions are fixed.

Dissociation of potassium chloride in water: KCl(aq) → K⁺(aq) + Cl⁻(aq).

4) Answer is: metal cation + nonmetal anion(–ide).

Name of this compound is calcium chloride.

Calcium chloride is a inorganic salt with ionic bonds between calcium and chlorine. It is a colorless crystalline solid at room temperature, highly soluble in water.

Calcium has oxidation number +2 and chlorine has oxidation number -2.

5) Answer is: AlCl₃.

Balanced chemical reaction: 2Al(s) + 3Cl₂(g) → 2AlCl₃(s).

Aluminium chloride is a salt with ionic bonds.

Aluminium (metal from group 13) has oxidation number +3 and chlorine (nonmetal from group 17) has oxidation number -1, chemical compound has neutral charge (+3 + 3 · (-1) = 0).

6) Answer is: carbon.

In molecule of methane (CH₄) all the atoms around the central element (carbon) are equivalent (four hydrogens) and it has a net dipole moment of 0 (vectors of dipole moments cancel each other, dipole moment is zero).

Methane (CH₄) is gaseous molecule with tetrahedrale structure, carbon is sp3 hybridized.

7) Answer is: Sodium chloride has a higher boiling point than sucrose.

Sodium chloride (NaCl) has ionic bonds and sucrose (C₁₂O₂₂O₁₁) has covalent bonds.

Sucrose or table sugar (C₁₂O₂₂O₁₁) composed of two monosaccharides. Monosaccharides glucose and fructose are linked with an ether bond between C1 on the glucosyl subunit and C2 on the fructosyl unit.

Boiling point of sodium chloride is 1413°C and sucrose decomposes at 186°C and form caramel.

8) Answer is:  It is a salt of three polyatomic ammonium ions and one polyatomic phosphate ion.

Polyatomic ammonium cation has charge of +1 and polyatomic phosphate anion has charge -3.

Ammounium ion is polyatomic because it is composed of one nitrogen and four hydrogen atoms.

Phospate anion is polyatomic because it is composed of one phosphorus and four oxygen atoms.

9) Answer is: S and O.

Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

Oxygen (O) has greater electronegativity than sulfur (S), oxygen is partially negative and sulfur is partially positive.

Sulfur and oxygen can form, for example, SO₃²⁻ (sulfite anion) or SO₄²⁻ (sulfate anion).

10) Answer is: manganese(II) phosphate.

Manganese (II) phosphate (Mn₃(PO₄)₂) is an ionic salt.

Manganese has oxidation number +2 and phosphate has charge -3.

3 · (+2) + 2 · (-3) = 0; chemical compound has neutral charge.

Formula for manganese(III) phosphate  is MnPO₄.

Formula for manganese(I) phosphate  is Mn₃PO₄.

points

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