Consider the model of the nitrogen atom. Three concentric circles are shown. Inside the inmost circle are the labels P-7 and N-7. The center circle has red dots at the north and south positions. The outer circle has five red dots evenly spaced around the circle; none of them align with dots in the center ring.

Which electron configuration matches this model?

1s22s22p2

1s22s22p3

1s22s22p4

1s22s22p5

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)

What type of matter is made of only one kind of atom