Isotopes of the same element always have the same atomic number because the atomic number is like the identity of each element and if it is changed the element is changed for example isotopes of Carbon are: ₆C¹² , ₆C¹³ and ₆C¹⁴ and if we change the atomic number form 6 to 7 we will have Nitrogen element ₇N¹⁴
So the correct answer is Z- number (atomic number)
The first one is 2
The second is 1
The third is 6
And the fourth is 3
A or c probably I think a tho
Answer:
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.
28. unbalanced because in reactant side the Aluminium is 1 and oxygen is 2 but in the product side the Aluminium is 2 and oxygen is 3 it is not equal so it is unbalanced equation
29. unbalanced because the oxygen atom are not equal in the reactant and the product side
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