Electron Configurations and Energy Levels

Teacher Adam introduces isotopes, explaining their definition and providing examples with hydrogen and carbon. The video covers energy levels and electron configurations, detailing how electrons are distributed in atoms. It also demonstrates drawing electron configurations for elements like boron, phosphorus, and potassium. The session concludes with extended questions and a brief on the first 20 elements of the periodic table.

What is the main characteristic that differentiates isotopes of the same element?

• Different atomic numbers

• Different numbers of protons

• Different numbers of neutrons

• Different chemical symbols

Which of the following is an example of isotopic representation?

• O2

• NaCl

• C-12 and C-14

• H2O

What is the maximum number of electrons the first energy level can hold?

• 2

• 8

• 18

• 32

For the first 20 elements, how many electrons can the third energy level hold?

• 18

• 32

• 8

• 2

What is the electron configuration of oxygen?

• 1s2 2s2 2p5

• 1s2 2s2 2p3

• 1s2 2s2 2p6

• 1s2 2s2 2p4

How many electrons does sulfur have in its third energy level?

• 6

• 8

• 4

• 2

What is the electron configuration of calcium?

• 1s2 2s2 2p6 3s2 3p6 4s2

• 1s2 2s2 2p6 3s2 3p6 3d2

• 1s2 2s2 2p6 3s2 3p6 4p2

• 1s2 2s2 2p6 3s2 3p6 4d2

How many electrons are in the outermost energy level of potassium?

• 1

• 2

• 3

• 4

Which element has the electron configuration 2, 8, 5?

• Sulfur

• Chlorine

• Nitrogen

• Phosphorus

Which of the following is NOT one of the first 20 elements in the periodic table?

• Potassium

• Argon

• Iron

• Calcium