If a neutral element has 8 neutrons and 7 electrons,which expression correctly identifies the element?
A) $\begin{array} { c }
15 \
7
\end{array}$ N
B) $\begin{array} { c }
8 \
15
\end{array}$ O
C) $\begin{array} { c }
15 \
8
\end{array}$ O
D) $\begin{array} { c }
7 \
8
\end{array}$ O
E)cannot tell from information given

Question

If a neutral element has 8 neutrons and 7 electrons,which expression correctly identifies the element?
A) $\begin{array} { c } 
15 \
7
\end{array}$ N
B) $\begin{array} { c } 
8 \
15
\end{array}$ O
C) $\begin{array} { c } 
15 \
8
\end{array}$ O
D) $\begin{array} { c } 
7 \
8
\end{array}$ O
E)cannot tell from information given

Quizplus · Accepted Answer

The atomic number (number of protons) is equal to the number of electrons in a neutral atom. Here, there are 7 electrons, so there are 7 protons. The mass number is the sum of protons and neutrons, which is 7 + 8 = 15. Therefore, the correct notation is $\begin{array} { c } 15 \ 7 \end{array}$ N, indicating nitrogen with a mass number of 15 and an atomic number of 7.

If a Neutral Element Has 8 Neutrons and 7 Electrons,which 157\begin{array} { c } 15 \\7\end{array}157​

If a Neutral Element Has 8 Neutrons and 7 Electrons,which $\begin{array} { c } 15 \\7\end{array}$