An element A has the configuration `1s^(2)2s^(2) 2p^(6)3s^(1)`and the element B has the configuration `1s^(2)2s^(2)2p^(4)` Give the formula of the compound formed.

Answer

To determine the formula of the compound formed between elements A and B, we need to analyze their electronic configurations and deduce their valence electrons.

### Step 1: Identify the elements based on their electronic configurations.

- **Element A** has the electronic configuration:
\[ 1s^2 2s^2 2p^6 3s^1 \]
This configuration indicates that element A has 1 electron in its outermost shell (3s). This matches the configuration of sodium (Na), which is in Group 1 of the periodic table.

- **Element B** has the electronic configuration:
\[ 1s^2 2s^2 2p^4 \]
This configuration indicates that element B has 6 electrons in its outermost shell (2s and 2p). This matches the configuration of oxygen (O), which is in Group 16 of the periodic table.

### Step 2: Determine the valence electrons.

- **Element A (Sodium)** has 1 valence electron.
- **Element B (Oxygen)** has 6 valence electrons.

### Step 3: Determine how many of each element is needed to form a stable compound.

- Oxygen needs 2 more electrons to complete its octet (8 electrons in total).
- Sodium can donate its 1 valence electron to oxygen. Therefore, to satisfy the requirement of oxygen, we need 2 sodium atoms.

### Step 4: Write the formula of the compound.

Since 2 sodium atoms are needed to bond with 1 oxygen atom, the formula of the compound formed will be:
\[ \text{Na}_2\text{O} \]

### Final Answer:
The formula of the compound formed is \(\text{Na}_2\text{O}\).

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