Unit 03 Review

Compared to the nonmetals in Period 2 of the Periodic Table, the metals in Period 2 generally have greater —

• atomic numbers.

• electronegativities.

• atomic radii.

• ionization energies.

Answer explanation

The metals in the 2nd period are to the left of the nonmetals. According to periodic trends this means they would have a larger atomic radii, smaller electronegativities, and smaller ionization energies.

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When a nonmetal is hit with a hammer it will crumble or break. Metals on the other hand will bend when it is hit. What physical property is indicated?

• conductivity

• permeability

• malleability

• ductility

Answer explanation

If a substance can be shaped it is considered to be malleable.

The picture shows a covalent molecule.

What molecule listed below has the same shape?

• BH₃

• H₂O₂

• NH₃

• Na₃P

Answer explanation

Which of the following best describes a metallic bond?

• attraction between positive ions and surrounding electrons

• attraction between negative ions with the sharing of electrons

• attraction between positive ions and negative ions

• attraction between positive ions to neutral atoms

Answer explanation

A metallic bond exists between the nuclei of metal atoms and the surrounding electrons.

Which of the following molecules has a central atom with precisely two unshared pairs of electrons?

• ammonia (NH₃)

• methane (CH₄)

• water (H₂O)

• cyanic acid (HCN)

Answer explanation

The correct Lewis structure for water has 2 pair of unshared electrons.

Which element in Period 3 of the Periodic Table has the greatest tendency to gain electrons?

• Cl

• Ar

• Na

• Si

Answer explanation

Chlorine is the most electronegative element in Period 3.

Tags

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Which particles are represented by the dots in Lewis valence e-dot structures?

• core electrons

• valence electrons

• protons

• all electrons

Answer explanation

Lewis dot structures contain only valence electrons.

What is a property of most metals?

• They tend to lose electrons easily when bonding.

• They tend to gain electrons easily when bonding.

• They are poor conductors of electricity.

• They are poor conductors of heat.

Answer explanation

Metals tend to lose electrons when bonding. They do not gain electrons and they are good conductors of heat & electricity.

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What is the molecular shape of a CCl₄ molecule?

• bent

• linear

• tetrahedral

• trigonal planar

Answer explanation

Carbon tetrachloride has 4 bonding sites and no lone pairs. The molecule is tetrahedral.

Which of these elements is the most electronegative?

• argon

• chlorine

• phosphorus

• sulfur

Answer explanation

The elements in Group 18 exhibit no electronegativity. For that reason chlorine is the most electronegative element.

Tags

NGSS.HS-PS1-1

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