Calculate the number of atoms in 10.0g of He.
A. 3.83 x 1023
B. 2.41 X 1024
C. 1.51 X 1024
D. 6.02 x 1023

Read the given expression. x = number of protons − number of core electrons which of the following explains the identity of x and its trends across a period? x is the effective nuclear charge, and it remains constant across a period. x is the screening constant, and it remains constant across a period. x is the effective nuclear charge, and it increases across a period. x is the screening constant, and it increases across a period.

Which of the following elements would you expect to have the lowest ionization energy value? fluorine, lithium, neon, nitrogen

How are isotopes of the same chemical element alike? how are they different?