INV 2.4 Daily Check Electrons in Atoms

Which of the following descriptions of the electron dot structure corresponds to an element in the s block?

• has three unpaired dots
• has an unpaired dot
• has two pairs of dots and two unpaired dots
• has three pairs of dots and an unpaired dot

Refer to the periodic table and the electron dot model of nitrogen. Based on the understanding of the way elements are arranged in the periodic table, which element will have the same number of valence electrons as nitrogen?

• As
• B
• O
• Si

Consider the electron configuration of sulfur. How many unpaired electrons does sulfur have?

• 0
• 1
• 2
• 4

The atomic number of an element is 15. What is the likely electron configuration arrangement of the valence and core electrons in a neutral atom of this element?

• There are 3 valence electrons and 12 core electrons.
• There are 4 valence electrons and 11 core electrons.
• There are 5 valence electrons and 10 core electrons.
• There are 6 valence electrons and 9 core electrons.

An atom of chlorine has 17 electrons. These electrons are present in energy levels around the nucleus. Which series of numbers lists the correct number of electrons in each energy level, starting with the energy level closest to the nucleus?

• 2, 8, 1
• 2, 8, 7
• 2, 8, 17
• 2, 10, 5