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a) 0.20 cm b) 1.7 cm c) 8 cm d) 6.4X103 cmm 2) Here are three isotopes of an ele

ID: 715630 • Letter: A

Question

a) 0.20 cm b) 1.7 cm c) 8 cm d) 6.4X103 cmm 2) Here are three isotopes of an element: 13C a. The element is: b. The number 6 refers to the c. The numbers 12, 13, and 14 refer to the d. How many neutrons are in the first isotope? e. How many protons are in the second isotope? f. How many protons and neutrons are in the third isotope? Rubidium is a soft, silvery-white metal that has two common isotopes, Rb and "Rb.If the abundance of Rb is 80.2% and the abundance of 87Rb is 19.8% what is the average atomic mass of rubidium? 3)

Explanation / Answer

2)

a) the element is Carbon

b) the number 6 refers to the atomic number of an element (here carbon)

c) the number 12, 13, 14 refers to the atomic mass of the different isotopes of the carbon.

d) mass number = no of neutron + no of protons

no of protons = atomic number

mass number = no of neutrons + atomic number

for first isotope mass number =12

no of neutrons = 12 - 6 = 6

no of the neutron is first isotope = 6

e) no of protons = atomic number

so no of protons in second isotope = 6

f) mass number = 14

no of protons = atomic number = 6

no of neutrons = 14 - 6 = 8