Chemistry 1

Question 1

What are the basic features of the three subatomic particles?

Answer 1

Question 2

Generally, which electrons determine the reactivity of an atom?

Answer 2

valence electrons

Question 3

Which electrons experience the least electrostatic draw to their nucleus?

Which are most likely to form a bond?

Answer 3

Those in the outermost energy level, or shell, called the valence electrons, experience the least electrostatic draw to their nucleus and so are much more likely to become involved in bonds with other atoms (filling empty spaces in other atoms’ valence shells)

Question 4

Avogadro’s number

Answer 4

(6.02 × 10²³).

Question 5

amu

Answer 5

mass of one proton is defined as approximately one amu. The size of the atomic mass unit is defined as exactly 1/12 the mass of the carbon-12 atom, approximately 1.66 × 10− 24 grams (g).

Question 6

atomic mass

Answer 6

the mass number (sum of protons and neutrons) of the atom

Question 7

atomic weight.

Answer 7

mass in grams of one mole of atoms of a given element and is expressed as a ratio of grams per mole (g/mol).

Question 8

Energy of a Quantam

Answer 8

Question 9

angular momentum of an electron

Answer 9

Bohr predicted, is quantized according to the following equation:

L = nh/2π

where h is Planck’s constant and n is the quantum number, which can be any positive integer. Because the only variable is the quantum number, n, the angular momentum of an electron changes only in discrete amounts with respect to the quantum number.

Question 10

energy of the electron

Answer 10

Question 11

Rydberg constant (R_H)

Answer 11

2.18 × 10^{− 18} J/electron.

Question 12

ground state

Answer 12

the orbit with the smallest radius in which hydrogen’s electron could be found was called the ground state and corresponded to n = 1.

Question 13

electromagnetic energy

Answer 13

where h is Planck’s constant, c is the speed of light in a vacuum (3.00 × 108 m/s), and λ is the wavelength of the radiation.

Question 14

Balmer series

Answer 14

• The group of hydrogen emission lines corresponding to transitions from the upper energy levels n > 2 to n = 2
• that is, the pattern of photon emissions from the electron falling from the n > 2 energy level to the n = 2 energy level)
• includes four wavelengths in the visible region.

Question 15

Lyman series

Answer 15

The group corresponding to transitions from the upper energy levels n > 1 to n = 1 (that is, the emissions of photons from the electron falling from the higher energy levels to the ground state) is called the Lyman series, which includes larger energy transitions and therefore shorter photon wavelengths in the UV region of the electromagnetic spectrum.

Question 16

The energy of the emitted photon corresponds to the precise ________ in energy between the __________ and _____________.

Answer 16

The energy of the emitted photon corresponds to the precise difference in energy between the higher-energy initial state and the lower-energy final state.

Question 17

What is Δ E with respect to absorption and emission?

Answer 17

Δ E is the same for absorption or emission between any two energy levels. The sign (positive or negative) of Δ E indicates whether the energy goes in or out and, therefore, whether the electron is going to an excited state (absorption) or to the ground state (emission), respectively.