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Atomic structure and isotopes

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Question 2

Early pioneers in chemistry contributed significantly to our understanding of atomic structure and the organization of the Periodic Table.

a.

Explain which block in the Periodic Table magnesium belongs to.

[2]
b.

A sample of magnesium, Ar=24.305A_r = 24.305Ar​=24.305, is found to consist of three isotopes. The accurate relative isotopic masses and % abundances of two of the isotopes are shown in the table:

IsotopeRelative isotopic mass% abundance
24Mg^{24}\text{Mg}24Mg23.98523.98523.98578.99%78.99\%78.99%
25Mg^{25}\text{Mg}25Mg24.98624.98624.98610.00%10.00\%10.00%

Determine the relative isotopic mass of the third isotope of magnesium, 26Mg^{26}\text{Mg}26Mg, in the sample. Give your answer to 5 significant figures.

[3]
c.

A student adds potassium oxide to water in a beaker. In a separate beaker, the student adds magnesium oxide to water.

Write the equation for the reaction of potassium oxide with water. State symbols are not required.

[1]
d.

Suggest the approximate pH of the two solutions formed in the beakers.

[2]

Atomic structure and isotopes Questions

  1. A Level
  2. /Chemistry
  3. /Atomic structure and isotopes