5.3 Electron Configuration

A quantum is the minimum amount of energy that can be lost or gained by an atom, while a photon is a particle of light that carries a quantum of energy.

Describe the difference between a quantum and a photon.

Single electrons with the same spin occupy each equal-energy orbital before additional electrons with opposite spins occupy the same orbital.

Describe the sequence in which ten electrons occupy the five orbitals related to an atom's d sublevel

118 electrons. [Rn]7s²5f¹⁴6d¹⁰7p⁶

Extend the Aufbau sequence through an element that has not yet been identified, but who's atoms would completely fill 7p orbitals. How many electrons would such an atom have? Write its electron configuration using noble-gas notation for the previous noble gas, radon.

[Kr] 5s²4d¹⁰5p² ∙Sn∙

For an atom of tin in the ground state, write the electron configuration using noble-gas notation, and draw its electron-dot structure.

a) 4 b) 7 c) 2 d) 3

How many electrons are shown in each element's electron dot structure? a) carbon b) iodine c) calcium d) gallium

Pauli exclusion principle, Aufbau principle, and Hund's rule

When writing the electron configuration notation for an atom, what three principles or rules should you follow?

d) [Ar] 4s²3d⁸4p¹

Which electron configuration notation describes an atom in an excited state? a) [Ar] 4s²3d¹⁰4p² b) [Ne] 3s²3p⁵⁵ c) [Kr] 5s²4d¹ d) [Ar] 4s²3d⁸4p¹

b

Which element could have the ground-state electron-dot diagram shown? a) manganese b) antimony c) calcium d) samarium

c is correct; a shows three two-electron orbitals; b shows one three-electron orbital; d has the wrong symbol

Which is the correct electron-dot structure for an atom of selenium? Explain.

a

Which orbital diagram is correct for an atom in its ground state?

a) Be: 1s²2s² 1s: ↑↓, 2s: ↑↓ b) Al: 1s²2s²2p⁶3s²3p¹ 1s: ↑↓, 2s: ↑↓, 2p: ↑↓ ↑↓ ↑↓, 3s: ↑↓, 3p: ↑ c) N: 1s²2s²2p³ 1s: ↑↓, 2s: ↑↓, 2p:↑ ↑ ↑ d) Na: 1s²2s²2p⁶3s¹ 1s: ↑↓, 2s: ↑↓, 2p: ↑↓ ↑↓ ↑↓, 3s: ↑

Write each element's orbital notation and complete electron configuration a) beryllium b) aluminum c) nitrogen d) sodium

electrons in an atom's outermost orbital

Define valence electron

5; 11

A chlorine atom in its ground state has a total of seven electrons in orbitals related to the atom's third energy level. How many of the seven electrons occupy p orbitals? How many of the 17 electrons in a chlorine atom occupy p orbitals?

aluminum; 3 electrons

An atom of an element has a total of 13 electrons. What is the element, and how many electrons are shown in its electron-dot structure?

18; 15; 4

An atom of arsenic has how many electron-containing orbitals? How many of the orbitals are completely filled? How many of the orbitals are associated with the atom's n=4 principal energy level?

indium

An element has the ground-state electron configuration [Kr]5s²4d¹⁰5p¹. It is part of some semiconductors and used in various alloys. What element is it?

[Xe]6s²; barium

In its ground state, an atom of an element has two electrons in all orbitals related to the atom's highest energy level for which n=6. Using noble-gas notation, write the electron configuration for this element, and identify the element.

Each orbital must contain a single electron before any orbital contains two electrons

In what sequence do electrons fill the atomic orbitals related to a sub level?

Light exhibits wavelike behavior in some situations and particle like behavior in others

Light is said to have a dual wave-particle nature. What does this statement mean?

beryllium

This element exists in the solid state at room temperature and at normal atmospheric pressure and is found in emerald gemstones. It is known to be one of the following elements: carbon, germanium, sulfur, cesium, beryllium, or argon. Identify the element based on the electron-dot structure.

a) Kr [Ar] 4s²3d¹⁰4p⁶ b) P [Ne] 3s²3p³ c) Zr [Kr] 5s²4d² d) Pb [Xe] 6s²4f¹⁴5d¹⁰6p²

Use noble-gas notation to describe the electron configurations of the elements represented by the following symbols a) Kr b) P c) Zr d) Pb

The orbital related to the 5s sub level has a lower energy than orbitals related to the 4d and 4f sublevels

Using Figure 5.24, explain why one electron in a rubidium atom occupies a 5s orbital rather than a 4d or 4f orbital

Valence electrons are the electrons in an atom's outermost orbitals; 2

What are valence electrons? How many of a magnesium atom's 12 electrons are valence electrons?

a) F b) Ca c) Nd d) Te e) Md f) Br

What element is represented by each electron configuration? a) 1s²2s²2p⁵ b) [Ar] 4s² c) [Xe] 6s²4f⁴ d) [Kr] 5s² 4d¹⁰5p⁴ e) [Rn] 7s²5f¹³ f) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵

6

When a sulfur atom reacts with other atoms, electrons in orbitals related to the atom's third energy level are involved. How many such electrons does a sulfur atom have?

a) Si 1s²2s²2p⁶3s²3p² b) F 1s²2s²2p⁵ c) Ca 1s²2s²2p⁶3s²3p⁶4s² d) Kr 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

Write out the full electron configurations for the following elements: a) silicon b) fluorine c) calcium d) krypton

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

Write the aufbau sequence of orbitals from 1s to 7p.

Oxygen: 1s²2s²2p⁴ The orbital diagram has five boxes with two arrows in the first three and single arrows in the last two. Sulfur: [Ne]3s²3p⁴ The orbital diagram has nine boxes with two arrows in the first seven and single arrows in the last two

Write the electron configuration and draw the orbital notation for atoms of oxygen and sulfur.

a) [Ar]4s²3d¹⁰4p⁵ b) [Kr]5s² c) [Kr]5s²4d¹⁰5p³ d) [Xe]6s²4f¹⁴5d⁵ e) [Xe]6s²4f⁹ f) [Ar]4s²3d²

Write the ground state electron configurations for the following elements a) bromine b) strontium c) antimony d) rhenium (Re) e) terbium (Tb) f) titanium