There are 18 Elements in the fifth period.
Answer:
<h2>
<em>an</em><em>swer</em><em> will</em><em> be</em><em> </em><em>D</em></h2>
<em>change</em><em> </em><em>of</em><em> </em><em>sta</em><em>te</em><em> </em><em>only</em><em> </em>
J. J. Thomson is the corect awncer
Left side metals right side non metals. arrganged in groups (columns) and periods (rows), each group tells you amount of valence electrons
