Question

Question
1
Question
2
Question
3
A)
The element radium has a mass number of 226 and an atomic number of 88. How many neutronsdoes an atom of radium have?
(1 point)
226
88
138
314
A)
Which phrase describes
transmutation
?
(1 point)
the conversion of protons to neutrons through nuclear changes
the conversion of energy to matter through chemical changes
the conversion of one substance to another through chemical changes
the conversion of an atom of one element into a different element through nuclear changes
A)
Which statement about the balanced equations for nuclear and chemical changes is correct?
(1 point)
Both are balanced according to the total mass before and after the change.
A nuclear equation is balanced according to mass number. A chemical equation is balanced according tothe number of atoms before and after the change.
A chemical equation is balanced according to mass number. A nuclear equation is balanced according tothe number of atoms before and after the change.
Both are balanced according to the number of atoms of each element before and after the change.
Question
4
Question
5
A)
Polonium has a mass number of 212 and an atomic number of 84. In a balanced nuclear reaction,polonium releases an alpha particle to produce lead. Which option is the atomic number of lead?
(1 point)
82
208
80
210
A)
Which statement best explains why mass is not conserved in a nuclear change?
(1 point)
Some of the atoms are lost in the reaction.
Some of the reactants are not used.
Some of the matter is converted to energy.
Some of the products have less mass than the reactants.

Answer 1

Here are the answers with brief reasons:

1) 138 — Neutrons = mass number − atomic number = 226 − 88 = 138.

2) the conversion of an atom of one element into a different element through nuclear changes — that is the definition of transmutation.

3) A nuclear equation is balanced according to mass number. A chemical equation is balanced according to the number of atoms before and after the change. — nuclear equations conserve mass number and atomic number; chemical equations conserve atom count.

4) 82 — Emission of an alpha particle (He, Z=2) reduces atomic number: 84 − 2 = 82.

5) Some of the matter is converted to energy — mass can be converted to energy in nuclear reactions (E = mc^2).