Electron Configuration and Atomic Structure

The video tutorial explains how to determine the element represented by an electron configuration ending in 3d7 4s2. It introduces two methods: counting the total number of electrons to find the atomic number, and using the periodic table to identify the element, which is cobalt. The tutorial also covers how to abbreviate electron configurations using noble gases, specifically argon, and discusses the order of electron filling in orbital blocks. The video concludes by reiterating the two methods for identifying elements from electron configurations.

What is the first step in identifying an element from its electron configuration?

• Look for the element's symbol.

• Identify the noble gas.

• Count the number of electrons.

• Count the number of protons.

How many electrons are present in the electron configuration ending in 3d7 4s2?

• 28

• 25

• 26

• 27

What does the atomic number of an element represent?

• The number of neutrons

• The number of electrons

• The number of valence electrons

• The number of protons

Which element is represented by the electron configuration with atomic number 27?

• Cobalt

• Copper

• Nickel

• Iron

What is the noble gas used to abbreviate the electron configuration of cobalt?

• Neon

• Krypton

• Argon

• Helium

How is the abbreviated electron configuration of cobalt written?

• [He] 3d7 4s2

• [Kr] 3d7 4s2

• [Ar] 3d7 4s2

• [Ne] 3d7 4s2

What are valence electrons?

• Electrons in the outermost shell

• Electrons in the p orbital

• Electrons in the d orbital

• Electrons in the innermost shell

In which order are the 4s and 3d orbitals sometimes written in electron configurations?

• 4s before 3d

• 3d before 4s

• 4p before 3d

• 3p before 4s

What is the significance of orbital blocks in the periodic table?

• They help identify the atomic mass.

• They help identify the electron configuration.

• They help identify the number of neutrons.

• They help identify the number of protons.

Which two methods can be used to identify an element from its electron configuration?

• Using neutrons and orbital blocks

• Using atomic mass and valence electrons

• Counting electrons and using noble gases

• Counting protons and using atomic mass