Lightest metal among the following is

Options

A. Na
B. Ca
C. Li
D. Mg

Answer

To determine the lightest metal among the given options (sodium, calcium, lithium, magnesium), we can follow these steps:

### Step 1: Identify the Metals
The first step is to identify which of the given options are metals. The options are:
- Sodium (Na)
- Calcium (Ca)
- Lithium (Li)
- Magnesium (Mg)

All of these elements are metals.

### Step 2: Check Their Positions on the Periodic Table
Next, we can look at the periodic table to understand the positions of these metals:
- Lithium (Li) is in Group 1 (alkali metals) and Period 2.
- Sodium (Na) is in Group 1 (alkali metals) and Period 3.
- Magnesium (Mg) is in Group 2 (alkaline earth metals) and Period 3.
- Calcium (Ca) is in Group 2 (alkaline earth metals) and Period 4.

### Step 3: Compare Atomic Masses
Now, we need to compare their atomic masses:
- Lithium (Li): approximately 7 u
- Sodium (Na): approximately 23 u
- Magnesium (Mg): approximately 24 u
- Calcium (Ca): approximately 40 u

### Step 4: Identify the Lightest Metal
From the atomic masses listed above, we can see that lithium has the lowest atomic mass (7 u). Therefore, it is the lightest metal among the options provided.

### Conclusion
The lightest metal among the options given is **lithium (Li)**.