Q: A photon of light has a wavelength of $$\lambda = 400\ \mathrm{nm}. $$What is its energy in joules? (Use $$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s}$$ and $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$E = \dfrac{hc}{\lambda} = 4.97 \times 10$$^{-19}$$\ \mathrm{J}$$

Question 1

Which statement best describes the shell model of the atom?

Accepted Answer

Electrons occupy discrete energy levels or shells around the nucleus.

Question 2

Which of the following correctly describes the trend in atomic size across a period in the periodic table?

Accepted Answer

Atomic size decreases from left to right due to increasing nuclear charge.

Question 3

A photon of light has a wavelength of $$\lambda = 400\ \mathrm{nm}. $$What is its energy in joules? (Use $$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$ and $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$E = \dfrac{hc}{\lambda} = 4.97 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 4

Photoelectron spectroscopy is used to determine which property of atoms?

Accepted Answer

The ionization energies of electrons in different shells.

Question 5

Which electron configuration represents a neutral atom of oxygen?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 6

Which quantum number describes the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 7

Which of the following molecules has a resonance structure?

Accepted Answer

$$NO_3$$^-$$

Question 8

Calculate the formal charge on the central atom in $$SO_2$$ using the following Lewis structure: $$O=S-O ($$both oxygens have lone pairs, sulfur has one lone pair).

Accepted Answer

+1

Question 9

Which statement best explains why $$H_2O is a $$polar molecule?

Accepted Answer

The oxygen atom is more electronegative than hydrogen, and the molecule has a bent shape.

Question 10

Which hybridization is found in the carbon atom of methane ($$CH_4$$)?

Accepted Answer

$$sp^3$$

Question 11

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

Accepted Answer

$$\sigma$$ bonds result from end-to-end overlap, $$\pi$$ bonds from side-to-side overlap.

Question 12

Which molecule has the largest dipole moment?

Accepted Answer

$$NH_3$$

Question 13

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases across a period and decreases down a group.

Question 14

Which of the following is a correct application of molecular orbital theory to $$O_2$$?

Accepted Answer

$$O_2 is $$paramagnetic because it has two unpaired electrons in its molecular orbitals.

Question 15

Which functional group is present in acetic acid ($$CH_3COOH$$)?

Accepted Answer

Carboxylic acid

Question 16

A greenhouse gas absorbs infrared radiation due to which molecular property?

Accepted Answer

It has a permanent dipole moment or can undergo a change in dipole moment during vibration.

Question 17

Which of the following best explains the concept of partial charge in a covalent bond?

Accepted Answer

Partial charge arises when electrons are shared unequally due to differences in electronegativity.

Question 18

Which of the following is the correct Lewis structure for $$NH_4$$^+$$?

Accepted Answer

Nitrogen with four single bonds to hydrogen and no lone pairs, with a positive charge.

Question 19

Which statement about electron spin is correct?

Accepted Answer

Two electrons in the same orbital must have opposite spins ($$m_s = +\frac{1}{2}$$ and $$m_s = -\frac{1}{2}).$$

Question 20

A molecule has the following electron configuration: $$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^5. $$What element is this?

Accepted Answer

Chlorine

General Chemistry Study Guide: Atomic Structure, Quantum Mechanics, and Chemical Bonding

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