For the following questions, use a periodic table and your atomic calculations to find the unknown information about each isotope: You have an neutrally charged isotope with a mass number of 99 and an atomic number of 43. Which element is it? Tc: Technetium Es: Einsteinium Xe: Xenon Sc: Scandium

Explanation:

Atomic number is the number of protons found in the element's atom. Since it has atomic number 43, we find the 43rd element in the Periodic table, which is Technetium. (Tc)

P.S. Mass number is the number of protons and neutrons in the element's atom

h let me think

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.