Question 1

Which of the following electron configurations violates the Aufbau Principle?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^3$$\ $$3s^1$$

Question 2

What is the ground state electron configuration for fluorine ($$Z = 9$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^5$$

Question 3

Which of the following is the correct condensed electron configuration for aluminum ($$Z = 13$$)?

Accepted Answer

$$[Ne]\ 3s^2$\ 3p^1$

Question 4

Which element has the following ground state electron configuration: $$[Ar]\ 4s^2$\ 3d$$^{10}$$\ 5p^2$?

Accepted Answer

Tin (Sn)

Question 5

Which of the following orbital diagrams correctly represents the electron configuration for phosphorus ($$Z = 15$$)?

Accepted Answer

Three unpaired electrons in the $$3p$$ orbitals

Question 6

Which of the following best describes the Aufbau Principle?

Accepted Answer

Electrons fill the lowest energy orbitals first before moving to higher energy orbitals.

Question 7

What is the condensed electron configuration for zinc ($$Z = 30$$)?

Accepted Answer

$$[Ar]\ 4s^2$\ 3d$$^{10}$$

Question 8

Which of the following statements about condensed electron configurations is correct?

Accepted Answer

They use the symbol of the nearest noble gas in brackets to represent core electrons.

Question 9

Which of the following electron configurations represents a violation of Hund's Rule?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$\ with two electrons paired in one $$2p$$ orbital and the other two $$2p$$ electrons unpaired

Question 10

Which element has the following condensed electron configuration: $$[Xe]\ 6s^2$\ 4f$$^{14}$$\ 5d$$^{10}$$\ 6p^2$?

Accepted Answer

Lead (Pb)

Question 11

A chemist is analyzing an unknown element and finds its electron configuration is $$[Ar]\ 4s^2$\ 3d^6$. Which element is this?

Accepted Answer

Iron (Fe)

Question 12

Which of the following is the correct electron configuration for a manganese(II) ion ($$Mn^{2+}$$, $$Z = 25$$)?

Accepted Answer

$$[Ar]\ 3d^5$

Question 13

Which of the following best explains why the $$4s$$ orbital is filled before the $$3d$$ orbital?

Accepted Answer

The $$4s$$ orbital is lower in energy than the $$3d$$ orbital when empty.

Question 14

Which of the following is the correct electron configuration for chlorine ($$Z = 17$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^5$$

Question 15

Which of the following is the correct condensed electron configuration for manganese ($$Z = 25$$)?

Accepted Answer

$$[Ar]\ 4s^2$\ 3d^5$

Question 16

Which of the following is the correct order of filling for the first four subshells according to the Aufbau Principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s$$

Question 17

Which of the following elements has a valence electron configuration of $$ns^2$$\ $$np^3$$?

Accepted Answer

Phosphorus (P)

Question 18

Which of the following is the correct electron configuration for a $$Zn^{2+}$$ ion?

Accepted Answer

$$[Ar]\ 3d$$^{10}$$

Question 19

Which of the following is the correct condensed electron configuration for lead ($$Z = 82$$)?

Accepted Answer

$$[Xe]\ 6s^2$\ 4f$$^{14}$$\ 5d$$^{10}$$\ 6p^2$

Electron Configuration and the Aufbau Principle: Study Notes

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