Valence Electrons and Electron Configuration

The video tutorial explains two main methods to determine the number of valence electrons for strontium (Sr). The first method involves using the periodic table, where group trends indicate that elements in group two, like strontium, have two valence electrons. The second method involves examining the electron configuration, specifically the highest energy level, which confirms that strontium has two valence electrons. The tutorial also demonstrates how to write the Lewis structure for strontium, showing the placement of its valence electrons.

What is the first method mentioned for finding the number of valence electrons in strontium?

• Observing chemical reactions

• Measuring atomic radius

• Calculating atomic mass

• Using the periodic table

Which group in the periodic table contains elements with two valence electrons?

• Group 18

• Group 13

• Group 2

• Group 1

How many valence electrons do elements in Group 13 have?

• 4

• 3

• 2

• 1

What is the highest energy level in the electron configuration of strontium?

• 4th energy level

• 3rd energy level

• 6th energy level

• 5th energy level

In the electron configuration of strontium, what does '5s2' indicate?

• Two electrons in the 5p orbital

• Five electrons in the s orbital

• Two electrons in the 5s orbital

• Five electrons in the p orbital

How should the Lewis structure for strontium be represented?

• Sr with two dots

• Sr with three dots

• Sr with no dots

• Sr with one dot

What is the total number of valence electrons in strontium?

• One

• Two

• Three

• Four