9. Give the number of protons, neutrons, and electrons in an atom of the \"Sr is

Question

9. Give the number of protons, neutrons, and electrons in an atom of the "Sr isotope. a, 52 p, 38 n. 52 e d. 38 p, 52 n, 38 e b, 38 p, 90 n, 38 e c, 38 p, 38 n, 38 e e, 90 p, 38 n, 90 e 10. Calculate the molarity of a solution that contains 70.0 g ofHaso, in 280. ml. ofsolution. d. 9.78 M b, 2.55 M e, 11.84 M c, 8.62 M 11. Isotopes are atoms of the same element that a. have different nuclear charges. b, have different numbers of protons. d, have different numbers of electrons e, have different numbers of Deutrons. c. have different atomic numbers. 12. How many grams of KoH are contained in 400, mLofo.250 MKOH solution? a. 89.8 g. d, 35.1 g b, 8.98 g e, 5.61 g e, 12.4 g 13. Simple positively charged ions are always than the neutral atoms from which they are formed. d. smaller b, larger c, the same size 14. The number of can change without changing the element. d, all of the above e. neutrons and electrons only protons only 15. is a noble gas. 16. The number of electrons in a neutral atom of an element is always equal to the of the element. b- isotope number e, atomic mass unit 17. A 10.0-L nask contains o 400 mole ofH,.0300 mole ofHe and 0.500 mole of Ne at 350c. What is the partial pressure of the Ne? 1.26 atm b, 0.144 atm e. 3.03 atm c. 1.69 atm

Explanation / Answer

answer 9

option d is correct

38 protons because your element is Sr

for neutrons take the isotope number 90 and -38 protons and you get 52 neutrons
the sum of the protons and neutrons give you the isotope number

and you have 38 electrons because thats what required to have a neutral charge with 38 protons

answer 10

Molarity = moles of solute/L of solution

First, convert grams of H2SO4 into moles by dividing by its molar mass. The molar mass of H2SO4 is 98.0785.
70/98.0785 = 0.7137 moles

Also convert 280 mL into L by dividing by 1000.
280/1000 = .28 L

M = mol/L
M = .7137/.28
M = 2.548 M option B is correct

answer 11

Different isotopes of the same element have the same atomic number. They have the same number of protons. The atomic number is decided by the number of protons. Isotopes have different mass numbers, though, because they have different numbers of neutrons.

answer 12

option e is correct

answer 13

Simple positively charged ions (cations) are always smaller than the neutral atoms from which they are formed

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