which of the following elements has the fewest valence electrons?\no beryllium\no boron\no carbon\no lithium

Explanation:

Step1: Determine valence - electrons of beryllium

Beryllium (Be) has an atomic number of 4. Its electron - configuration is 1s²2s². The number of valence electrons is 2.

Step2: Determine valence - electrons of boron

Boron (B) has an atomic number of 5. Its electron - configuration is 1s²2s²2p¹. The number of valence electrons is 3.

Step3: Determine valence - electrons of carbon

Carbon (C) has an atomic number of 6. Its electron - configuration is 1s²2s²2p². The number of valence electrons is 4.

Step4: Determine valence - electrons of lithium

Lithium (Li) has an atomic number of 3. Its electron - configuration is 1s²2s¹. The number of valence electrons is 1.

Answer:

lithium