A certain isotope X contains 23 protons and 28 neutrons. Determine the mass number of this isotope and identify the element. Which element, isotope, or ion listed below contains 35 protons, 46 neutrons, and 36 electrons? 7. 8. 81Kr+ b. 81Br c. 81Kr d. 81Br- 9. and horizontal rows are vertical columns found on a periodic table are called called 10. How many of the following is/are true about the element fluorine? Fluorine is a halogen Fluorine is in period 2 of the periodic table. Fluorine is a nonmetal Fluorine is in Group 7A IV 11. An ion with a 3+ charge contains 23 electrons. Which ion is it? a. Fe3* 12. True or False Two isotopes of the same element differ only in the number of protons found in b. V3* c. Ca3+ d. Sc3+ the nucleus 13. Which of the following pairs are isotopes? A) Ca+2 and Mg+2 B) 199Hg and 200Hg C) 180 and 19F D) 238U and 238Np 14. In nature, "Valentinium" consists of two isotopes, Valentinium-69 (Mass 68.926 with natural abundance of 60.1%) and Valentini um-71 (Mass = 70.925 with natural abundance of 39.9%). Calculate the relative atomic mass of the element "Valentinium". (2 points)