chem 201 ch 3 key concepts

Which of the following is true concerning successive ionizations of an atom and its ions?

Each successive ionization requires increasing amounts of energy.

What element has the symbol F?

Fluorine

If light has a lot of energy, it will have

A small wavelength ( feed back The relationship between energy and wavelength is shown. E=hcλE=hcλ If the energy is high that means the wavelength will be small/short.)

What is the formula for an ionic compound containing Ba²⁺ ions and Cl⁻ ions?

BaCl2 (feedback Two ions of chlorine are needed to balance out the positive charge on the barium ion.)

The element symbol for potassium is _____

K

Which of the following is most likely to form a +2 ion?

Mg

Which element has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d⁵?

Mn

Which of the following is best classified as a covalent compound

N2O5 ( feedback A covalent bond occurs between two nonmetals.)

Of the following compounds, which contains a metalloid?

SiF4 ( feedback Metalloids are elements that have properties of both metals and nonmetals. The metalloids are: B, Si, Ge, As, Sb, Te and Po.)

The element symbol for tin is

Sn

Which of the following elements would be chemically similar to calcium (Ca)?

Sr

Which of the following is best classified as an ionic compound?

ZnS(feedback An ionic bond occurs between a metal and a nonmetal)

In the photoelectric effect, if the intensity of light shone on a metal increases, what will happen?

there will be more electrons ejected ( Ephoton=Φ+KE)

If a hydrogen (H) atom and a helium (He) atom travel at the same speed, which of the following is true about the de Broglie wavelengths of the atoms?

)The H atom is about 4 times longer than the He atom. ( feedback The de Broglie equation treats moving particles like waves, and states that the wavelength (λ) of these particles is inversely proportional to their momentum, or the product of their mass (m) and velocity (v). λ=hmv)

What is the maximum number of electrons that can have the following set of quantum numbers? n = 4, ℓ = 3, mℓ = 3, ms = -½

1

If n = 2, what is the maximum allowed value for ℓ?

1( feedback The following solution may contain one or more values that are different from the problem provided to you, however, the steps to solve the problem are the same. .According to the rules governing acceptable quantum numbers, the value for ℓ can only be as high as n-1. If n = 2, the maximum value for ℓ is 1.)

For a hydrogen atom, calculate the wavelength of light (in m) that would be emitted for the orbital transition of n(initial) = 2 to n(final) = 1. Submit an answer to four significant figures. The Rydberg constant is 1.09678 x 10⁷ m⁻¹.

1.216x10-7

What is the energy of a mole of photons that have a wavelength of 705 nm?

1.70 x105 J (feedback E=hcλ E=(6.626×10−34J⋅s)(3.00×108m/s)7.05×10−7mE=2.81957x10-19J 2.81957×10−19J/1photon×6.02×1023photons/1mol=1.70×105J

What is the energy, in J, of light that must be absorbed by a hydrogen atom to transition an electron from n = 3 to n = 6? Submit an answer to three signficant figures.

1.82x10-19J

How many electrons can be assigned to orbitals designated by the quantum numbers n = 3, ℓ = 2?

10

In a ground state atom of Kr how many electrons total will have the quantum number ℓ = 2?

10

The ground state electron configuration of an Al atom is

1s²2s²2p⁶3s²3p¹

What is the electron configuration of K⁺?

1s²2s²2p⁶3s²3p⁶

What is the electron configuration of Co²⁺?

1s²2s²2p⁶3s²3p⁶3d⁷

The ground state electron configuration of a Se atom is

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁴

Which of the following is the electron configuration of a neutral Fe atom?

1s²2s²2p⁶3s²3p⁶4s²3d⁶

When an electron in excited energy level drops to a lower energy level, a photon is emitted. If the electron is dropping to n=1, which transition will emit the longest wavelength? n=______ to n=1.

2 ( feedback The transition from n=2 to n=1 will be the lowest energy (longest wavelength) transition.)

What is the wavelength (in nm) of a photon if the energy is 7.26 × 10⁻¹⁹ J? (h = 6.626 × 10⁻³⁴ J • s)

273nm 7.26×10−19J=(6.626×10−34J⋅s)(3.00×108m/s)/2.74x10-7m 2.74x10-7m x 1x109nm/1m =274nm

Which quantum state (n,ℓ,mℓ) is NOT possible?

3,0,1(feedback The value for mℓ must be between -ℓ and ℓ, so if ℓ = 0, mℓ must 0 as well. As such, the quantum state (n = 3, ℓ = 0, mℓ = 1) is not possible.)

Calculate the wavelength in meters of electromagnetic radiation that has a frequency of 980.0 kHz. (c = 3.00 X 10⁸ m/s)

306.12 m ( feedback c=νλ 980.0kHz×1000 Hz/1kHz=9.800×105 Hz=9.800×105 s−1 λ=c/v=3.00×108m/s9.800×105s−1=306.1 m

Which of the following orbitals cannot exist?

3f ( feedback Atomic orbitals are described by their principal quantum number (n) followed by a letter that corresponds to the value for the angular momentum quantum number (ℓ), which corresponds to the following values: s = 0, p = 1, d = 2, f = 3. According to the rules governing acceptable quantum numbers, the value for ℓ can only be as high as n-1. Based on these rules, the 3f orbital (n = 3, ℓ = 3) cannot exist.)

For which atomic orbital does n = 3 and ℓ = 1?

3p ( feedback Atomic orbitals are described by their principal quantum number (n) followed by a letter that corresponds to the value for the angular momentum quantum number (ℓ). Here, n = 3, so the atomic orbital symbol will begin with 3. The quantum number ℓ = 1 (s = 0, p = 1, d = 2, f = 3), which corresponds to p. Therefore, this is a 3p atomic orbital.)

In a multi-electron atom, which orbital will have the highest energy?

4f ( feedback The energy of an electron is primarily dictated by its principal quantum number, n. For atoms with multiple electrons, electrons that have the same value of n (as is the case here, with n = 4) will have higher energies with higher values of ℓ. Of these options, the 4f orbital has the highest value of ℓ (ℓ = 3), so it will have the highest energy.)

Determine the energy of a photon with a wavelength of 364 nm.

5.47x10-19J (feedback E= hc/λ E=(6.626×10−34J⋅s)(3.00×108m/s)3.64×10−7mE=5.46×10−19J

A photon has a frequency of 8.6 × 10⁸ Hz. What is the energy of this photon?

5.7x10-25 j (feedback E=hv E=(6.626×10−34J⋅s)(8.6×1081/s)E= 5.7x10-25J

How many electrons can be assigned to orbitals designated by the quantum numbers n = 2, ℓ = 1?

6

The halogens are found in Group ____

7A (17)

What is the formula of a compound containing Al³⁺ and S²⁻ ions?

Al2S3 (feedback Two aluminum ions are needed to balance out the negative charge on the three sulfur ions. This is the lowest number of each ion to reach a neutral formula unit.)

which of the following pairs of ions represent isoelectronic species?

Al³⁺ and O²⁻

the element symbol for arsenic is

As

Predict the chemical formula for the ionic compound formed by Au³⁺ and HSO₃⁻

Au(HSO3)3

Which of the following is an alkaline earth metal?

Beryllium ( feedback the alkaline earth metals are found in group 2 and include Be Mg Ca Sr Ba and Ra)

Which of the following is a main group element?

Bismuth (feedback The main group elements are elements that belong to the s and p blocks of the periodic table.)

Predict the chemical formula for the ionic compound formed by Ca²⁺ and ClO₃⁻

Ca(ClO3)2

Which of the following is an ionic compound?

CaO

What type of bonding is present in C₁₂H₂₂O₁₁?

Covalent bonds only

the element symbol for copper is

Cu

Predict the chemical formula for the ionic compound formed by Cu²⁺ and P³⁻

Cu3P2

Einstein's work on the photoelectric effect validated and made extensive use of which of the following equations?

E=hv

What element is designated by the orbital diagram below?

F( feedback This orbital diagram contains a total of 9 electrons (1s²2s²2p⁵). Since the question is asking for an element and not an ion, the element must have the atomic number 9, meaning that this element must be F.)

All of the following pairs of ions are isoelectronic except which one?

Fe²⁺ and Mn³⁺

What group (G) and period (P) does the element molybdenum (Mo) belong to?

G=6 P=5 (feedback Molybdenum is found in the 6th column (Group 6) and the fifth row (Period 5) of the periodic table.)

Which of the following compounds does not contain a polyatomic ion?

H2S

The atomic radii of zirconium (Zr) and hafnium (Hf) are nearly the same despite the fact that hafnium has 32 more protons and electrons. Which of the following bests explains this phenomenon?

Hafnium contains electrons in the 4f orbitals these 4f electrons do not effectively shield the higher nuclear charge and thus Zeff is higher than might be otherwise expected

Because electron energy levels are quantized, which of the following is true? I) Atomic emission spectra are a series of discrete lines. II) Atomic emission spectra are continuous. III) Electrons may only occupy a discrete set of energy levels. IV) Electrons may occupy a continuous range of energy levels.

I and III (feedback The quantization of electron energy levels leads to a set of discrete transitions between those levels, which produces a set of discrete emission lines at specific wavelengths of light.)

Consider these electron transitions in a hydrogen atom: I. n = 2 → n = 1 II. n = 3 → n = 1 III. n= 1 → n = 4 Which of the electron transitions would release the most energy?

II n=3 > n=1

Excited hydrogen atoms emit radiation in which region(s) of the electromagnetic spectrum?

IR, visible, and UV (Excited hydrogen atoms are capable of emitting radiation with wavelengths from 100 nm to 10,000 nm; this section of the electromagnetic spectrum includes IR, visible, and UV radiation.)

Which periodic trend quantifies the amount of energy required to remove an electron from a neutral, gaseous atom?

Ionization Energy (Ionization energy is the amount of energy required to remove an electron from a neutral, gaseous atom.)

What is the noble gas core in the electron configuration for Ru?

Kr (feedback The noble gas core for a given element is the last noble gas filled in the periodic table prior to the given element. Here, the last noble gas prior to Ru is Kr, so that is its noble gas core.)

Which of the following electron configurations is incorrect?

Mn [Ar]4s²4d⁵

Considering periodic trends, valence electrons in which of the following atoms experience the greatest effective nuclear charge (Zeff)?

Ne ( feedback The Zeff increases from left to right in the periodic table.)

Which element is classified as a noble gas?

Neon (Ne) (feedback Noble gases are found in column 18 of the periodic table. Neon is a noble gas.)

Which of the following series of isoelectronic ions (Mg²⁺, N³⁻, F⁻, Si⁴⁺) has the ionic radii in order of largest to smallest?

N³⁻ > F⁻ > Mg²⁺ > Si⁴⁺

Which of the following states that no two electrons can have the same set of four quantum numbers?

Pauli exclusion principle (feedback The Pauli exclusion principle states that no two electrons in a given atom can share the same set of four quantum numbers (n, ℓ, mℓ, ms).

Which of the following is NOT a metalloid?

Pb ( feedback Metalloids are elements that have properties of both metals and nonmetals. Lead (Pb) is a metal. The metalloids are: B, Si, Ge, As, Sb, Te and Po)

Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N.

Rb < Mg < B < N < F (feedback In general, first ionization energy decreases down a group and increases across a period.)

Rank the following atoms in order of decreasing size (i.e., largest to smallest): Rb, F, Mg, B, N.

Rb>Mg>B>N>F

In which direction in a given period of the periodic table does melting point tend to increase?

The closer an atom is to having a half full valence shell the higher the melting point ( high in the 'middle' of the period and low at the end

Which of these statements is true concerning the following reaction? Na(g) → Na⁺(g) + e⁻.

This is an ionization process.

What is the atomic symbol for the element in Group 4B (4) and the fourth period?

Ti

Which electron configuration violates Hund's rule?

[He] 2s2 2px2 2py2

Which of the following is the electron configuration for Ba?

[Xe]6s²

Which color (frequency) of light travels the fastest in a vacuum?

all have the same speed (feedback The speed of light is constant in a vacuum and all colors of light travel the same speed.)

An atom has nine protons and ten electrons. This makes it:

an ion (feedback A neutral atom has an equal number of protons and electrons. If there are more or less of one than the other, the atom is an ion.)

Based on the positions of the following elements on the periodic table, which of them would you expect to form a 3+ cation?

both a scandium and b aluminm

The symbol Cr represents the element _____

chromium

Energy of a photon is ______ proportional to frequency, and _______ proportional to wavelength.

directly, inversely (feedback The energy (E) of a photon of light is proportional to its frequency (ν) or the inverse of its wavelength (λ) multiplied by Planck's constant (h): E=hν=hcλ)

In which direction on the periodic table does metallic character increase?

down and to the left (feedback Metallic character increases down and to the left of the periodic table.)

The trend towards smaller atomic radii as one moves to the right in a period is _____.

due to the effective nuclear charge increasing. ( feedback The trend toward smaller atomic radii as one moves to the right in a period is due to the effective nuclear charge increasing.)

The energy released in the reaction F(g) + e⁻ → F⁻(g) is known as the

electron affinity

What happens to the energy of a photon if the wavelength is doubled?

energy is reduced by one - half (feed back The relationship between energy and wavelength is shown. E=hc/λ If the wavelength is doubled the energy would be reduced by half.)

What type of light on the electromagnetic spectrum has the highest energy per photon?

gamma waves (feedback Energy is directly related to frequency and inversely related to wavelength. Since gamma waves have the highest frequency and shortest wavelength, they have the highest energy.)

In the Bohr model of the hydrogen atom, the energy required to excite an electron from n = 2 to n = 3 is _______________ the energy required to excite an electron from n = 3 to n = 4?

greater than (feedback ΔEi→f=R(1n2f−1n2i) ΔE2→3=R(132−122)=−0.14R ΔE3→4=R(142−132)=−0.05R ∣ΔE2→3∣>∣ΔE3→4∣

Columns on the periodic table are known as

groups ( feedback Columns on the periodic table are known as groups.)

What quantum mechanics principle states that electrons are added to atomic orbitals with the same energy so that each orbital is singularly occupied with electrons having the same spin?

hund's rule (feedback Hund's rule states that electrons are added to the atomic orbitals with the same energy levels (degenerate orbitals) in such a way that each orbital is occupied by a single electron with the same spin (either +½ or -½) before any orbital can be occupied by two electrons.)

Elements that are most similar in their properties are found _____

in the same group. ( feedback Elements that are in the same group have similar properties.)

What is observed when a noble gas is heated and the emitted light shone through a prism?

individual lines of varying colors ( feedback Heating a noble gas promotes its electrons to excited energy states, which then relax to emit discrete wavelengths of light. When shone through a prism, this results in individual lines of varying colors.)

What type of bonding is present in SrCl₂?

ionic bond only (feedback SrCl₂ is an ionic compound. Each unit cell contains one Sr²⁺ cation and two Cl⁻ anions. Only ionic bonds are present in this compound.)

Classify the following compounds as ionic or covalent: BaO, Fe₂O₃, ZnO.

ionic, ionic, ionic (feedback Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two nonmetals.)

Red light has a _____ frequency and a _____ wavelength than ultraviolet rays.

lower, longer ( feedback The electromagnetic spectrum shows that red light has a longer wavelength than ultraviolet rays. The relationship between wavelength and frequency is shown.c=λνc=λν Wavelength and frequency are inversely related, so if it has a longer wavelength than ultraviolet rays, it also has a shorter frequency than ultraviolet rays.)

Which of the following groups of elements tend to form cations?

metals (feedback metals tend to form cation)

Carbon dioxide is a _____ compound composed two types of _____ atoms.

molecular nonmetal (feedback Carbon dioxide is a molecular compound composed of two oxygen atoms with covalent double bonds to a central carbon atom. Both C and O are to the right of the "staircase" on the periodic table, as nonmetals.)

Which of the following sets of quantum numbers can describe a 3p electron?

n = 3, ℓ = 1, mℓ = 1 ( feedback Atomic orbitals are described by their principal quantum number (n) followed by a letter that corresponds to the value for the angular momentum quantum number (ℓ). For a 3p electron, the number 3 represents n, whereas s represents ℓ. ℓ corresponds to the following values: s = 0, p = 1, d = 2, f = 3; this means that in this orbital, ℓ = 1. The value for mℓ must be between -ℓ and ℓ, so if ℓ = 1, mℓ must be -1, 0, or 1)

A ground state atom of As could not have any electrons with which of the following configurations?

n = 4, ℓ = 2, mℓ = 0, ms = +½ (feedback This is a 4d electron, which is not found in an As atom.)

If ℓ = 0, which of the following may be true?

n=6 (feedback The value for mℓ must be between -ℓ and ℓ, so if ℓ = 0, mℓ must 0 as well. The value for ms must be either +1/2 or -1/2, so it cannot be 1 or 0. The value of ℓ must be less than the value of n, so ℓ = 0 and n = 6 is acceptable.)

Similar properties recur periodically when elements are arranged according to increasing atomic number is the statement of the ______.

periodic law

Which of the following is NOT a rare earth (lanthanide) element?

protactinium (feedback Protactinium (Pa) is an actinide, with atomic number 91. The lanthanides are elements with atomic numbers 57-71.)

Which type of electromagnetic radiation has the largest wavelength?

radio waves ( feedback The electromagnetic spectrum ranges from radiation with the shortest wavelength (highest frequency) to longest wavelength (lowest frequency). Of the various types of radiation, radio waves have the longest wavelength.)

Which of the following is a transition metal?

silver

Which of the following metals would be expected to have the smallest atomic radius?

tantalum (ta) (feedback The atomic radius increases as you move down the periodic table and to the left. Tantalum is the furthest to the right of this list and nearer the top and it would be expected to have the smallest atomic radius.)

True or false: two electrons can simultaneously occupy the same (n,ℓ,mℓ) orbital.

true ( feedback The fourth quantum number, the spin number (ms), allows for two electrons to have the same n, ℓ, mℓ quantum numbers, but different values for ms.)

Light wave A has a greater frequency than light wave B. Which has a greater wavelength?

wave B ( feedback All light travels at the same speed (c), and since speed is equal to the product of wavelength and frequency, a higher frequency results in a shorter wavelength. Because wave A has a greater frequency than wave B, wave B must have the longer wavelength.)

Which element is classified as a transition metal?

zirconium (Zr) (feedback Transition metals are found in columns 3-12 of the periodic table. Zirconium is a transition metal found in column 4.)