Answer: The correct answer is 4-7.
Step-by-step explanation:
A non-metal is defined as the element which gains electron to attain stable electronic configuration and to attain a negative ion which is anion.
![X+ne^-\rightarrow X^(n-)](https://img.qammunity.org/2019/formulas/chemistry/high-school/unynkm0b8gbcsascz2ta5qrfzqqvffxia5.png)
Non-metals are the elements which belong to Group 14 to Group 17.
The valence electronic configuration of the elements:
- Belonging to Group 14 =
![ns^2np^2](https://img.qammunity.org/2019/formulas/chemistry/high-school/qn4d4pnqtdavt2dauxjhdzqypvyfitya55.png)
Number of valence electrons = 4
- Belonging to Group 16=
![ns^2np^3](https://img.qammunity.org/2019/formulas/chemistry/college/psb7txyuq2k6qu9mnigh41h74sc6kplzk3.png)
Number of valence electrons = 5
- Belonging to Group 16 =
![ns^2np^4](https://img.qammunity.org/2019/formulas/chemistry/middle-school/mw2jkdcrohuiz2ofsz1pqgs8od8wzdhnjb.png)
Number of valence electrons = 6
- Belonging to Group 17 =
![ns^2np^5](https://img.qammunity.org/2019/formulas/chemistry/high-school/mmm0x5lvvf0vrmsd6xgnoz0hvjb548ggr3.png)
Number of valence electrons = 7
Hence, the correct answer is 4-7.