1. How many moles is 4.25 x 1025 atoms of calcium?

The electron configurations of two different atoms are shown below. each yellow electron has a charge of 1−, and the net charge of each nucleus is shown. these atoms will combine with bond. a. an ionic b. a positive c. a negative d. a covalent plzzz mee with !

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg

What is the value of the standard enthalpy of formation of an element in its most stable form?