1. The atomic number is equal to the number of protons in an atom. How many protons are in a lithium atom?
3 4 5 6 7 8
Sc Ti V Cr Mn Fe 1
2. A neutral atom has the same number of electrons and protons.
Y Zr Nb Mo Tc Ru !
Hf Ta W Re Os
How many electrons are in a neutral lithium atom?
Average
atomic
mass
6.54
3. Select the ELECTRON CONFIGURATION tab, and check that Energy is selected. Click
twice in the 1s box at lower left and once in the 2s box. Observe the atom model at right.
A. What do you see?
B. Click Check. Is this electron configuration correct?