The atomic mass of an element is double its atomic number. If there are four electrons in the 2p-orbital, the draw the model of the atom showing the arrangement of protons, neutrons and electrons. Give its valence and name the element.

Explanation

To solve the problem step by step, we will follow the information given in the question and the video transcript.

### Step 1: Understand the relationship between atomic mass and atomic number
The question states that the atomic mass (A) of an element is double its atomic number (Z). This can be expressed mathematically as:
\[ A = 2Z \]

### Step 2: Determine the atomic number and atomic mass
Let’s denote the atomic number as \( Z \). According to the relationship:
\[ A = 2Z \]
If we assume \( Z = 8 \), then:
\[ A = 2 \times 8 = 16 \]
This means the element has an atomic number of 8 and an atomic mass of 16.

### Step 3: Identify the element
From the periodic table, we know that the element with atomic number 8 is oxygen (O).

### Step 4: Determine the electron configuration
The question states that there are 4 electrons in the 2p orbital. The electron configuration for oxygen can be written as:
- 1s² (2 electrons in the 1s orbital)
- 2s² (2 electrons in the 2s orbital)
- 2p⁴ (4 electrons in the 2p orbital)

Thus, the complete electron configuration for oxygen is:
\[ 1s^2 \, 2s^2 \, 2p^4 \]

### Step 5: Calculate the number of protons and neutrons
- **Protons**: The number of protons is equal to the atomic number, which is \( Z = 8 \).
- **Neutrons**: The number of neutrons can be calculated using the formula:
\[ \text{Neutrons} = A - Z = 16 - 8 = 8 \]

### Step 6: Draw the atomic model
The atomic model will consist of:
- **Nucleus**: Contains 8 protons and 8 neutrons.
- **Electrons**: Arranged in shells:
- 2 electrons in the 1s shell
- 2 electrons in the 2s shell
- 4 electrons in the 2p shell

### Step 7: Determine the valence
The valence of an element is determined by the number of electrons in the outermost shell. For oxygen, the outermost shell is the second shell (2s and 2p), which contains a total of 6 electrons (2 in 2s and 4 in 2p). Oxygen needs 2 more electrons to complete its octet, so its valence is 2.

### Summary of the solution:
- **Element Name**: Oxygen (O)
- **Atomic Number (Z)**: 8
- **Atomic Mass (A)**: 16
- **Protons**: 8
- **Neutrons**: 8
- **Electrons**: 8
- **Valence**: 2