Atomic Structure

Isotopes

100

⁶³Cu and ⁶⁵Cu both have the same number of __, but a different number of ___.

⁶³Cu and ⁶⁵Cu both have the same number of PROTONS, but a different number of NEUTRONS.

200

List the number of protons, electrons and neutrons in an atom of Tungsten-180.

Protons = 74
Electrons = 74
Neutrons = 106

300

Antimony-121 and Antimony-123 both occur naturally. Which isotope is more abundant? Justify your answer.

¹²¹Sb is more common in nature. This can be determined by comparing the mass numbers of the nuclides to the average atomic mass of antimony on the periodic table. Because the average atomic mass, 121.75 is closer to 121 than it is to 123, ¹²¹Sb must be more abundant.

400

There are two naturally occurring isotopes of Gallium. The nuclide that has an atomic mass of 68.9257 amu makes up 60.40% found in nature. What is the mass of the other isotope of gallium?

69.72 = [(.6040)(68.9257)] + [(.3960)(x)]

69.72 = 41.6311228 + .3960x

28.09 = .3960x

x = 70.93 amu

500

There are two naturally occurring isotopes of Chlorine. One isotope has a mass of 34.968853 amu, the other isotope has a mass of 36.965903 amu. Calculate their abundances.

35.45 = [(x)(34.968853)] + [(1 - x)(36.965903)]

35.45 =   34.968853x + 36.965903 - 36.965903x

-1.52 = -1.99705x

x = .761

³⁵Cl makes up 76.1% of the naturally occurring Cl, ³⁷Cl makes up the rest, 23.9%

Electron Config

100

Write electron configuration notation for phosphorus and phosphide

P = 1s²2s²2p⁶3s²3p³
P^3-=1s²2s²2p⁶3s²3p⁶

200

1s²2s²2p⁶6s² would be an example of a/an

excited atom (doesn't follow Aufbau ordering) because you would expect the valence electrons for this element to be in the 3rd energy level (have a principle quantum number, n, of 3), but instead they have a principle quantum number of 6 (in other words, the valence electrons have been promoted to the 6th energy level.

300

An orbital that has two up arrows disobeys...

the Pauli principle which states that two electrons in the same orbital should have opposite spin

400

Noble gas configuration for mercury would be

[Xe]6s²4f¹⁴5d¹⁰

500

Aluminum would be _______ (paramagnetic/diamagnetic) because it has __________________ .

Aluminum would be PARAMAGNETIC because it has at least one UNPAIRED ELECTRON.

↑  __ __ in 3p.

Being paramagnetic means the element would be attracted to a magnetic field.

Ionization Energy

100

Ionization energy _____ as you go across a period _____ as you go down a family

Ionization energy INCREASES as you go across a period and DECREASES as you go down a family

200

The second ionization energy for sodium would be ___ than the first ionization for sodium because

The second ionization energy for sodium would be HIGHER than the first ionization for sodium because the first valence electron removed would be on the 3rd energy level, and the second valence electron removed would be down on the second energy level, and it takes more energy to remove an electron that is closer to the nucleus

300

Which element in the third period would have the following ionization energies?
I₁ 578 kJ/mol
I₂ 1817 kJ/mol
I₃ 2745 kJ/mol
I₄ 11,577 kJ/mol
I₅ 14842 kJ/mol
I₆ 18,379 kJ/mol

Aluminum (It takes substantially more energy to remove the 4th electron, which means the element has 3 electrons in its outermost shell, therefore, the element is Al)

400

Write the BCE for the first three ionizations of sulfur.

S --> S¹⁺ + 1 e^-
S¹⁺ --> S²⁺ + 1 e^-
S²⁺ --> S³⁺ + 1 e^-

500

Chloride would have a lower first ionization energy than chlorine because

Chloride has a larger atomic radius than chlorine (same number of energy levels, same number of protons pulling, added ve^- in Cl^1- makes valence shell bigger), and because it takes less energy to remove an electron from a larger atom, I₁ is lower for Cl^1- than it is for Cl

Atomic/Ionic Radius

100

Iodine has a larger atomic radius than chlorine. Explain why.

Although both atoms have 7 valence electrons, an atom of iodine has 5 energy levels, whereas an atom of chlorine has only 3 energy levels. The additional energy levels of iodine make the atomic radius of iodine larger than the atomic radius of chlorine.

200

Sulfur has a smaller radius than silicon. Explain why.

Although both atoms have 3 energy levels, sulfur has 16 protons pulling (greater effective nuclear charge) compared to silicon, which only has 14 protons pulling.

300

The ionic radius of bromine is larger than the ionic radius of strontium. Explain why.

Although both ions are isoelectronic (same number of electrons), Sr²⁺ has more protons pulling on the valence shell, making the ionic radius of Sr²⁺ smaller than the ionic radius of Br^1-

400

The most metallic element on the periodic table is Fr because

it has the lowest ionization energy due to its large atomic radius.

500

The ionic radius for iodide is larger than the atomic radius of iodine. Explain why.

Both iodine and iodide have 5 energy levels, both iodine and iodide have 53 protons pulling on the valence shell, iodide has one additional electron in the valence shell. The additional repulsion of the added valence electron makes the valence shell of I^1-slightly larger than the valence shell of I, therefore the radius of iodide is slightly larger than the radius of iodine.