Ionic and Metallic Bonding

A particle-level diagram of a metallic element is shown above. Typically, metals are both malleable and ductile. The best explanation for these properties is that the electrons involved in bonding among metal atoms are

• unequally shared and form nondirectional bonds

• unequally shared and form highly directional bonds

• equally shared and form nondirectional bonds

• equally shared and form highly directional bonds

Copper atoms and zinc atoms have the same atomic radius, 135 picometers. Based on this information, which of the following diagrams best represents an alloy containing only copper and zinc atoms?

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NGSS.HS-PS1-3

Steel is an alloy containing Fe atoms and C atoms. Which of the following diagrams best represents the particle-level structure of steel?

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NGSS.HS-PS1-3

Which of the following diagrams best depicts an alloy of Ni and B?

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NGSS.HS-PS1-3

To make Au stronger and harder, it is often alloyed with other metals, such as Cu and Ag. Consider two alloys, one of Au and Cu and one of Au and Ag, each with the same mole fraction of Au. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table above?

• Cu has two common oxidation states, but Ag has only one.

• Cu has a higher melting point than Au has, but Ag has a lower melting point than Au has.

• Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy.

• Cu atoms are less polarizable than are Au or Ag atoms, thus Cu has weaker interparticle forces.

Tags

NGSS.HS-PS1-3

Steel is an alloy consisting of Fe with a small amount of C. Elemental Cr can be added to steel to make the steel less likely to rust; Cr atoms react with oxygen in the air to form a nonreactive layer of chromium oxide on the surface of the steel, preventing the oxidation of underlying Fe atoms. A sample of steel-chromium alloy contains 15 percent Cr by mass. Which of the following diagrams best shows a particle-level view of a surface section and an interior section of the alloy represented above? (The atomic radii of the atoms involved are given in the table above.)

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NGSS.HS-PS1-3

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following correctly indicates whether the solid represented by the particulate model shown above conducts electricity and explains why or why not?

• It conducts electricity because it is made of positive and negative ions.

• It conducts electricity because it is made of particles of different sizes.

• It does not conduct electricity because its ions cannot move freely within the solid.

• It does not conduct electricity because there are small spaces between the particles.

Tags

NGSS.HS-PS1-3

NGSS.HS-PS2-6

The particle-level diagram above represents the structure of solid KF. Although the molar mass of KCl is greater than that of KF, the density of KCl is actually less than that of KF. Which of the following representations of the structure of KCl best helps to explain this phenomenon?

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Tags

NGSS.HS-PS1-3

The energy required to dissociate an ionic solid into gaseous ions (lattice energy) for the compounds NaF

NaF and MgF₂ is shown in the table above. On the basis of Coulomb’s law, which of the following best helps to explain the large difference between the lattice energies of NaF

NaF and MgF₂?

• The solubility of MgF₂ is less than that of NaF.

• The electronegativity of Mg is greater than that of Na.

• The mass of the Mg cation is greater than that of the Na cation.

• The charge of the Mg cation is larger than that of the Na cation.

Tags

NGSS.HS-PS2-4

Which of the following diagrams best illustrates how a displacement in an ionic crystal results in cleavage and brittleness? The left image is before displacement, and the right image is after displacement.

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NGSS.HS-PS1-3

NGSS.HS-PS2-4