Question 1

Which of the following statements concerning the periodic table is incorrect?
A)The elements in a given group or family have similar chemical properties.
B)The chemical characteristics of the elements are periodic functions of their atomic numbers.
C)All the elements are arranged in order of increasing atomic weight.
D)Mendeleev left spaces in his periodic table for undiscovered elements.
E)Mendeleev received most of the credit for the early development of the periodic table.

Accepted Answer

The elements in the periodic table are arranged in order of increasing atomic number and not atomic weight.

Question 2

The statement that "the lowest-energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals" is known as
A)the aufbau principle.
B)Hund's rule.
C)the Pauli exclusion principle.
D)Heisenberg uncertainty principle.
E)the quantum model.

Accepted Answer

The statement given in the question is known as Hund's rule, which states that for a set of degenerate orbitals, the lowest-energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle. The aufbau principle refers to the order in which sublevels are filled with electrons, while the Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers. The Heisenberg uncertainty principle and the quantum model are both concepts in quantum mechanics but are not directly related to the statement given in the question.

Question 3

Who was the first chemist to recognize patterns in chemical properties of the elements?
A)Bohr
B)Dobereiner
C)Meyer
D)Mendeleev
E)Newlands

Accepted Answer

Johann Wolfgang Döbereiner was the first to recognize patterns in chemical properties of elements, known as Döbereiner's triads, which grouped elements with similar properties.

Question 4

In general,atomic radii
A)decrease from left to right in a period and increase down a group.
B)increase from left to right in a period and decrease down a group.
C)do not change across a period or a group.
D)decrease from left to right and decrease down a group.
E)increase from left to right in a period and increase down a group.

Accepted Answer

Atomic radii decrease from left to right across a period due to the increase in nuclear charge, which pulls the electrons closer to the nucleus. They increase down a group as additional electron shells are added, increasing the distance of the outermost electrons from the nucleus.

Question 5

How many unpaired electrons are found in the ground state electron configuration of silicon (Si)?
A)2
B)3
C)5
D)0
E)1

Accepted Answer

Silicon (Si) has an atomic number of 14, leading to an electron configuration of [Ne]3s^2 3p^2. In its 3p orbital, there are two unpaired electrons, making the correct answer 2.

Question 6

The element whose atoms in the ground state have two half-filled orbitals is
A)K.
B)Be.
C)Tl.
D)O.
E)As.

Accepted Answer

Oxygen (O) has the electron configuration 1s² 2s² 2p⁴, with two of its 2p orbitals half-filled in the ground state.

Question 7

Which of the following atoms is paramagnetic in its ground state?
A)sodium (Na)
B)nobelium (No)
C)neon (Ne)
D)mercury (Hg)
E)barium (ba)

Accepted Answer

Sodium (Na) has an unpaired electron in its 3s orbital, making it paramagnetic.

Question 8

Which of the following species would be expected to have chemical properties most similar to those of the nitrogen atom?
A)nitride ion
B)nitrite ion
C)phosphate ion
D)phosphide ion
E)phosphorus atom

Accepted Answer

Nitrogen and phosphorus are both located in the same group on the periodic table (group 15), meaning they have the same number of valence electrons and similar chemical properties. Therefore, the best choice for a species with chemical properties most similar to nitrogen would be the phosphorus atom (E).

Question 9

Which of the following orbital diagrams represents a diamagnetic atom?
1s 2s 2p
A) 
B) 
C) 
D) 
E)

Accepted Answer

The answer of Which of the following orbital diagrams represents...

Question 10

Which of the following statements is true?
A)The krypton 1s orbital is smaller than the helium 1s orbital because krypton's nuclear charge draws the electrons closer.
B)The krypton 1s orbital is smaller than the helium 1s orbital because krypton's p and d orbitals crowd the s orbitals.
C)The krypton 1s orbital and the helium 1s orbital are the same size because both s orbitals can have only two electrons.
D)The krypton 1s orbital is larger than the helium 1s orbital because krypton contains more electrons.
E)The krypton 1s orbital is larger than the helium 1s orbital because krypton's ionization energy is lower so it's easier to remove electrons.

Accepted Answer

The size of an orbital is determined by the nuclear charge and the effective nuclear charge experienced by the electrons. Krypton has a higher nuclear charge than helium, which draws the electrons closer to the nucleus, making the krypton 1s orbital smaller than the helium 1s orbital. The other options either don't make sense or are not relevant to the size of orbitals.

Question 11

An atom of which of the following elements has the smallest atomic radius?
A)P
B)Cl
C)S
D)Na
E)Si

Accepted Answer

Atomic radius decreases as you move from left to right across a period in the periodic table. Since Cl is on the right side of the period containing P, S, Na, and Si, it has the smallest atomic radius.

Question 12

Which principle or rule is violated by the following orbital diagram of an atom in its ground state?
1s 2s 2p

A)Heisenberg uncertainty principle
B)No rules or principles are violated by this orbital diagram.
C)aufbau principle
D)Hund's rule
E)Pauli exclusion principle

Accepted Answer

The answer of Which principle or rule is violated by...

Question 13

An atom of which of the following elements is not diamagnetic in the ground state?
A)Sr
B)Kr
C)All are diamagnetic.
D)Cd
E)Pt

Accepted Answer

Diamagnetism is a property of all materials and is due to the pairing of electrons. An atom is considered diamagnetic if all of its electrons are paired. Among the options, Strontium (Sr), Krypton (Kr), and Cadmium (Cd) have all electrons paired in their ground states, making them diamagnetic. Platinum (Pt), however, has unpaired electrons in its ground state configuration, making it not purely diamagnetic but paramagnetic.

Question 14

The ground-state electron configuration of a Mn²⁺ ion is 1s²2s²2p⁶3s²3p⁶3d⁵.Therefore,Mn²⁺ is A)paramagnetic with five unpaired electrons. B)diamagnetic. C)paramagnetic with one unpaired electron. D)paramagnetic with three unpaired electrons. E)paramagnetic with two unpaired electrons.

Accepted Answer

The given electron configuration shows five unpaired electrons in the 3d subshell, indicating that the ion is paramagnetic with five unpaired electrons.

Question 15

When arranged in order of increasing atomic number,the elements exhibit periodicity for all the following properties except
A)electron affinity.
B)color.
C)ionization energy.
D)electron configuration.
E)atomic radius.

Accepted Answer

Color is not a property that exhibits periodicity in the periodic table. The other properties listed (electron affinity, ionization energy, electron configuration, and atomic radius) all display trends and patterns as elements are arranged in order of increasing atomic number.

Question 16

Which of the following elements would be expected to have chemical and physical properties most similar to those of the krypton (Kr)?
A)neon (Ne)
B)gallium (Ga)
C)sodium (Na)
D)tin (Sn)
E)chlorine (Cl)

Accepted Answer

Krypton (Kr) and neon (Ne) are both noble gases and thus have very similar physical and chemical properties. They both have full outer electron shells, making them non-reactive, and have low boiling and melting points. In contrast, gallium (Ga), sodium (Na), tin (Sn), and chlorine (Cl) are all reactive elements with different physical properties, making them unlikely to have similar properties to Kr.

Question 17

Which of the following orbital diagrams represent(s)a paramagnetic atom?
1s 2s 3s
1) 
2) 
3) 
A)3 only
B)2 and 3
C)1 only
D)1 and 2
E)2 only

Accepted Answer

The answer of Which of the following orbital diagrams represent(s)a...

Question 18

A section of the periodic table with all identification features removed is shown below.
V
W
X
Y
Z
Which element has the smallest atomic radius?
A)W
B)Y
C)X
D)Z
E)V

Accepted Answer

Atomic radius generally decreases across a period from left to right.

Question 19

Which of the following orbital diagrams represents a paramagnetic atom?
1s 2s 2p
A)     
B)     
C)     
D)     
E)

Accepted Answer

The answer of Which of the following orbital diagrams represents...

Question 20

Fe has ____ that is(are)unpaired in its d orbitals.
A)2 electrons
B)3 electrons
C)1 electron
D)4 electrons
E)none of these

Accepted Answer

Iron (Fe) in its ground state has the electron configuration [Ar] 3d^6 4s^2. In the 3d subshell, there are 4 unpaired electrons.

Quiz 8: Electron Configurations and Periodicity

Which of the following statements concerning the periodic table is incorrect?

The statement that "the lowest-energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals" is known as

Who was the first chemist to recognize patterns in chemical properties of the elements?

In general,atomic radii

How many unpaired electrons are found in the ground state electron configuration of silicon (Si) ?

The element whose atoms in the ground state have two half-filled orbitals is

Which of the following atoms is paramagnetic in its ground state?

Which of the following species would be expected to have chemical properties most similar to those of the nitrogen atom?

Which of the following orbital diagrams represents a diamagnetic atom? 1s 2s 2p

Which of the following statements is true?

An atom of which of the following elements has the smallest atomic radius?

Which principle or rule is violated by the following orbital diagram of an atom in its ground state? 1s 2s 2p

An atom of which of the following elements is not diamagnetic in the ground state?

The ground-state electron configuration of a Mn²⁺ ion is 1s²2s²2p⁶3s²3p⁶3d⁵.Therefore,Mn²⁺ is

When arranged in order of increasing atomic number,the elements exhibit periodicity for all the following properties except

Which of the following elements would be expected to have chemical and physical properties most similar to those of the krypton (Kr) ?

Which of the following orbital diagrams represent(s) a paramagnetic atom? 1s 2s 3s 1) 2) 3)

A section of the periodic table with all identification features removed is shown below. V W X Y Z Which element has the smallest atomic radius?

Which of the following orbital diagrams represents a paramagnetic atom? 1s 2s 2p

Fe has ____ that is(are) unpaired in its d orbitals.