If you know the atomic number of all elements then its good.Now find its electric configuration. Metals always loses electrons and non metals gain and try to achieve the electronic configuration of its nearest noble gas like Na=2,8,1 so it will lose one electron to achieve electronic configuration of neon[10]. The intermediate element will be metalloid like between neon[10] and argon[18] sulphur[14] is intermediate element. so it is a metalloid. I hope it has cleared your doubt.

How to Identify Whether a Given Element is a Nonmetal Based on its Electronic Configuration

To determine whether a given element is a nonmetal based on its electronic configuration, we need to understand the characteristics and properties of nonmetals. Nonmetals are elements that lack metallic characteristics such as malleability, ductility, and conductivity. They generally have low melting and boiling points and tend to gain or share electrons in chemical reactions. Here's a step-by-step guide on how to identify a nonmetal using its electronic configuration:

Step 1: Understand Nonmetal Characteristics
Nonmetals have the following distinguishing characteristics:
- Poor conductors of heat and electricity
- Brittle and lack malleability and ductility
- Tend to gain or share electrons in chemical reactions
- Generally have low melting and boiling points
- Tend to form covalent compounds

Step 2: Determine the Element's Electronic Configuration
The electronic configuration of an element describes the arrangement of electrons in its atomic orbitals. It is represented by a series of numbers and letters that indicate the distribution of electrons into different energy levels and subshells.

Step 3: Analyze the Electronic Configuration
Once we have the electronic configuration of the element, we can analyze it to determine if the element is a nonmetal. Here are some key points to consider:

1. Valence Electrons:
- Nonmetals tend to have higher numbers of valence electrons (electrons in the outermost energy level).
- Valence electrons are responsible for the chemical properties of an element.
- Elements with 4 or more valence electrons are more likely to be nonmetals.

2. Electronic Configuration Patterns:
- Nonmetals are typically found on the right side of the periodic table (Groups 14-18).
- Elements with electronic configurations ending in s2p4, s2p5, s2p6, s2p3, s2p2, or s2p1 are often nonmetals.
- Nonmetals are commonly found in the p-block of the periodic table.

3. Ionization Energy:
- Nonmetals generally have higher ionization energies, meaning it requires more energy to remove an electron from their outermost energy level.
- Nonmetals tend to have higher electronegativity values, indicating a greater ability to attract electrons.

Step 4: Analyze the Overall Properties
After considering the electronic configuration, we can also examine the overall properties of the element to confirm if it is a nonmetal. These include:
- Physical properties such as low melting and boiling points
- Chemical properties such as a tendency to form covalent compounds
- Poor conductivity of heat and electricity

By following these steps and considering the characteristics, electronic configuration, and properties of nonmetals, we can determine whether a given element is a nonmetal or not.