H.W. #10 Unit 4 (Due 10/19/25)

Match each element with the number of energy levels occupied in its atom.

• Bromine

• 2

• Oxygen

• 4

• Sodium

• 3

• Hydrogen

• 1

Answer explanation

Electrons fill the energy levels in the order of increasing energy. Write the electron configurations and look at the principal quantum numbers .

What is the correct element to put in the [bracket] when writing the shortcut configuration of iodine?

• Ar

• Kr

• Xe

• Rb

• Cs

Answer explanation

The correct element to put in the bracket when writing the shortcut configuration of iodine is the noble gas that precedes iodine in the periodic table.

Tags

NGSS.HS-PS1-1

What is the total number of electrons in a shell with principal quantum number 4?

• 32

• 50

• 25

• 40

• 5

Answer explanation

In a shell with principal quantum number 4 there are s, p, d, and f orbitals. How many electrons are there in total?

What is the maximum number of electrons that can be found in a full set of 3p orbitals?

• 2

• 10

• 6

• 14

• None of these

Answer explanation

Consider the number of p orbitals per shell greater than or equal to n=2 and the Pauli Exclusion Principle.

What are the allowed orbital types for the second period of the periodic table (i.e., n = 2)?

• 1s

• 2s, 2p

• 2s, 2p, 2d

• 1s, 2s, 2p

• None of these

Answer explanation

For n = 2, the elements exist in the second period.

Tags

NGSS.HS-PS1-1

Consider the electron filling diagram Which of the following I) the aufbau principle; II) the Pauli exclusion principle; III) Hund’s rule does it violate?

(a)  

• I and II
• I and III

• II and III

• I only

• II only

• III only

Answer explanation

The diagram violates two of the rules for filling orbitals.

Tags

NGSS.HS-PS1-2

Consider the electron filling diagram:

Which of the following does it violate?

I) the aufbau principle; II) the Pauli exclusion principle; III) Hund’s rule.

• I only

• II only

• I and III

• I, II and III

• III only

Answer explanation

The diagram violates two of the orbital filling rules.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

A single f orbital can be occupied by a maximum of (a)   electrons.

• 2
• 6
• 7
• 10
• 14

Answer explanation

The Pauli exclusion principle states that no two electrons can have the same set of quantum numbers. Since the last quantum number has only two possible values, what does this mean for the orbital capacity?

If an electron is in the third principal energy level, in which type of orbital(s) could this electron be?

• s only

• p only

• s or p

• s or p or d

• d only

Answer explanation

An electron in the third principal energy level (n=3) can be in one of three different orbital types.

What is the ground-state electron configuration expected for beryllium?

• [He] 2s²

• [He] 2s¹2p¹

• [He] 4p²

• [He] 3s²

• [He] 3s¹3p¹

Answer explanation

Beryllium has 4 electrons.

Tags

NGSS.HS-PS1-1