Question

1. which element has the following electron configuration: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d⁶

a. fe
c. ru
b. tc
d. cd

1. which element has the following noble gas configuration: ar 4s²3d⁷

a. cobalt
c. iron
b. rhodium
d. sulfur

1. what is the next atomic orbital in the series 1s, 2s, 2p, 3s...

a. 4s
c. 3d
b. 4d
d. 3p

1. for an electron in an atom to change from the ground state to an excited state

a. the electron must make a transition from a higher energy level to a lower energy level
c. radio waves must be released
b. energy must be absorbed
d. energy must be emitted

1. visible light, x - rays, infrared radiation, and radio waves all have the same

a. energy
c. speed
b. frequency
d. wavelength

1. the letter \s\ in the symbol 3s² indicates that

a. orbital shape
c. speed of an electron
b. spin of an electron
d. principle energy level

1. which scientist developed the quantum mechanical model of the atom - the \cloud model\

a. j.j. thomson
c. niels bohr
b. erwin schrödinger
d. john dalton

1. which of the following electromagnetic waves have the highest frequencies?

a. gamma rays
c. x - rays
b. microwaves
d. ultraviolet waves

1. an atom of silicon contains 14 electrons. how many energy levels are needed to contain these electrons?

Explanation:

1. Calculate the total number of electrons from the electron - configuration. The atomic number is equal to the number of electrons. For $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{6}$, the sum of electrons is 44, and the element with atomic number 44 is Ru.
2. [Ar] represents 18 electrons, plus $4s^{2}3d^{7}$ (2 + 7 = 9 more electrons), a total of 27 electrons, which is Cobalt.
3. According to the Aufbau principle, after 3s, the next orbital is 3p.
4. An electron transitions from the ground state to an excited state by absorbing energy.
5. Visible light, X - rays, infrared radiation, and radio waves are all electromagnetic waves, and they all travel at the speed of light in a vacuum.
6. In the orbital notation like $3s^{2}$, "s" represents the orbital shape.
7. Erwin Schrödinger developed the quantum mechanical model of the atom (the "cloud model").
8. Among the given electromagnetic waves, gamma rays have the highest frequencies.
9. The electron - configuration of silicon (14 electrons) is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{2}$, which requires 3 energy levels (n = 1, n = 2, n = 3).

Answer:

1. c. Ru
2. a. Cobalt
3. d. 3p
4. b. energy must be absorbed
5. c. speed
6. a. orbital shape
7. b. Erwin Schrödinger
8. a. gamma rays
9. b. 3