Question 1

Which statement best explains why elements in the same group of the periodic table have similar chemical properties?

Accepted Answer

They have the same number of valence electrons.

Question 2

Which of the following electron configurations represents an atom with a completely filled third energy level?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$

Question 3

Which trend is observed in atomic radius as you move down a group in the periodic table?

Accepted Answer

Atomic radius increases due to the addition of electron shells.

Question 4

A sodium atom ($$Na) $$loses one electron to form $$Na^+. $$Which property increases as a result?

Accepted Answer

Ionization energy

Question 5

Which of the following best describes the bonding in metallic solids according to the electron sea model?

Accepted Answer

Electrons are delocalized and move freely throughout the metal lattice.

Question 6

Which molecule has a trigonal planar electron geometry according to VSEPR theory?

Accepted Answer

$$BF_3$$

Question 7

Which of the following statements about lattice energy is correct?

Accepted Answer

Lattice energy increases as the charge of the ions increases and the size decreases.

Question 8

Which of the following elements has the highest first ionization energy?

Accepted Answer

Fluorine ($$F)$$

Question 9

What is the formal charge on the central atom in the nitrate ion ($$NO_3$$^-$$) if the Lewis structure is drawn with one double bond and two single bonds to oxygen?

Accepted Answer

0

Question 10

Which of the following molecules is polar?

Accepted Answer

$$NH_3$$

Question 11

Which statement best describes the difference between sigma ($$\sigma) $$and pi ($$\pi) $$bonds?

Accepted Answer

$$\sigma$$ bonds result from end-to-end overlap of atomic orbitals, while $$\pi$$ bonds result from side-to-side overlap.

Question 12

Which hybridization is present in the central atom of $$CH_4$$?

Accepted Answer

$$sp^3$$

Question 13

Which of the following best explains why oxygen is more electronegative than sulfur?

Accepted Answer

Oxygen has a higher effective nuclear charge and smaller atomic radius.

Question 14

Which of the following ions has the smallest ionic radius?

Accepted Answer

$$Mg^{2+}$$

Question 15

Which of the following molecules contains a bond with the greatest percent ionic character?

Accepted Answer

$$HF$$

Question 16

Which statement about the octet rule is correct?

Accepted Answer

Elements in period 3 and beyond can have expanded octets.

Question 17

Which of the following best describes the molecular orbital theory for $$O_2$$?

Accepted Answer

$$O_2$$ has both bonding and antibonding molecular orbitals and is paramagnetic.

Question 18

Which of the following best explains why the boiling point of $$NaCl is $$much higher than that of $$H_2O$$?

Accepted Answer

NaCl has stronger ionic bonds than the hydrogen bonds in H2O.

Question 19

Which of the following is the correct order of increasing effective nuclear charge ($$Z_{eff}) $$for the elements $$Na$$, $$Mg$$, and $$Al$$?

Accepted Answer

$$Na \u003c Mg \u003c Al$$

Question 20

A molecule has a central atom with two lone pairs and two bonding pairs. What is its electron geometry and molecular shape?

Accepted Answer

Electron geometry: tetrahedral; molecular shape: bent

Exam 4 Review: Periodic Properties, Lewis Model, and Molecular Shapes (Ch. 9-11)

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