Physical Science Chapter 15

Part A: When metals bond with nonmetals, electrons are transferred from the metal to the nonmetal, resulting in the formation of an ionic compound. How many electrons are transferred between the cation and anion to form the ionic bond in one formula unit of each compound?

1 electron: LiCl, NaF, NaBr 2 electrons: BaO, CaS

Part B: Consider a covalent compound that is composed of a nitrogen atom (N), a hydrogen atom ( H ), and a carbon atom (C). How many electrons should the electron-dot structure of the covalent compound contain?

10

Part D: Based on your answer to part C, how many bonding electrons and nonbonding electrons are there in the electron-dot structure of HCN?

8,2

Rank the compounds in order of increasing symmetry: (a) Cl2O, (b) NCl3, (c) CCl4. Rank from least to most. To rank items as equivalent, overlap them.

A, B, C

Rank these bonds in order of increasing polarity: (a) C-H, (b) O-H, (c) N-H. Rank from least to most. To rank items as equivalent, overlap them.

A, C, B

How does an ion differ from an atom?

An atom with a net electric charge is an ion.

Part B: In each molecule, which atom carries the greater positive charge: Br−F?

Bromine

Rank these compounds in order of increasing boiling point: (a) iodine, I2; (b) ammonia, NH3; (c) methane, CH4. Rank from least to most. To rank items as equivalent, overlap them.

C, B, A

Part B: Arrange the molecules in order of decreasing boiling point. Rank the molecules from highest boiling point to lowest boiling point. To rank items as equivalent, overlap them.

C2H5OH HBr H2

Part C: In molecule, which atom carries the greater positive charge: C−O?

Carbon

Part A: Three of the fundamental types of intermolecular forces are induced dipole-induced dipole attraction (or dispersion forces), dipole-dipole forces, and hydrogen bonding. What intermolecular forces are present in each of the substances?

Dispersion forces only: C6H14, C2H6 Dispersion forces and dipole-dipole forces: HCN Dispersion forces, dipole-dipole forces, and hydrogen bonding: C6H5OH, NH3

How many electrons are shared in a double covalent bond?

Four

Part C: What is the electron-dot structure of the covalent compound that contains one nitrogen atom, one hydrogen atom, and one carbon atom given that the carbon atom is the central atom?

H-C(triple bond to N) & N with 2 dots

Part A: In molecule, which atom carries the greater positive charge: H−Cl?

Hydrogen

Magnesium ions carry a 2+ charge, and chloride ions carry a 1− charge. What is the chemical formula for the ionic compound magnesium chloride? Express your answer as a chemical formula.

MgCl2

Ores of manganese, Mn, sometimes contain the mineral rhodochrosite, MnCO3, which is an ionic compound of manganese ions and carbonate ions. How many electrons has each manganese atom lost to make this compound? Express your answer as an integer.

N= 2 electrons

Part B: What is the molecular formula for ammonium nitrate?

NH4NO3

Part A: Select the correct electron-dot formulas. You can refer to the periodic table if necessary.

Ne, Na, F

Part D: In molecule, which atom carries the greater positive charge: Br−Br?

Neither

Classify these molecules as polar or nonpolar.

Polar: Ch3Cl HF H2O Nonpolar: H2 CCl4 BCl3

Part C: Which nonmetals could form an ionic compound with magnesium with the formula MgX2 (where X represents the nonmetal)?

Possible: F Cl Br Not possible: O N S

Part B: Draw the electron-dot formula for the element sulfur. You can add the valence electrons by clicking on the or button and clicking the atom.

S with 2 sets of 2 dots and 2 single dots

Which molecule from each pair should have a higher boiling point (atomic numbers: Cl = 17, O = 8, C = 6, H = 1)?

The one with the most molecules.

Part A: For neutral molecules, which statements about covalent electron-dot structures are true?

True: For a neutral molecule, the number of electrons in the electron-dot structure is the sum of the valence electrons for the atoms, Electrons of covalent compounds may be shared between atoms. False: Hydrogen atoms are often the central atom of an electron-dot structure, Each atom of an electron-dot structure must have eight electrons.

Part B: Which of the following correctly represent the placement of electrons around each atom?

Valid: Na+[Br]- [F]-Ca2+[F}- Invalid: NaBr FCaF Na-[Br]- [F]+Ca2+[F}+

What is an alloy?

a mixture of two or more metallic elements

Part A: What is the name of the ionic compound BaCO3?

barium carbonate

Which electrons are represented by an electron-dot structure?

valence electrons