The First 20 Elements of The Periodic Table | PDF - Free Printable

The task is to fill in the table with information about the first 20 elements of the periodic table. Here's how to solve it step by step:

Known Information:

1. Element Name: The names of the first 20 elements are provided in the table.
2. Element Symbol: Each element has a unique symbol (e.g., H for hydrogen).
3. Atomic Number: This is the number of protons in the nucleus of an atom and also equals the number of electrons in a neutral atom.
4. Atomic Mass: This is the average mass of an atom of the element, usually given in atomic mass units (amu). It is approximately equal to the sum of protons and neutrons.
5. Number of Protons: Equal to the atomic number.
6. Number of Electrons: In a neutral atom, this is equal to the number of protons.
7. Number of Neutrons: Calculated as \( \text{Atomic Mass} - \text{Atomic Number} \) (rounded to the nearest whole number).

Solution:

We will fill in the table row by row using the periodic table as a reference.

#### Step-by-Step Filling of the Table:

| Element Name | Element Symbol | Atomic Number | Atomic Mass | Number of Protons | Number of Electrons | Number of Neutrons |
|----------------|----------------|---------------|-------------|--------------------|---------------------|---------------------|
| hydrogen | H | 1 | 1.008 | 1 | 1 | 0 |
| helium | He | 2 | 4.003 | 2 | 2 | 2 |
| lithium | Li | 3 | 6.941 | 3 | 3 | 4 |
| beryllium | Be | 4 | 9.012 | 4 | 4 | 5 |
| boron | B | 5 | 10.811 | 5 | 5 | 6 |
| carbon | C | 6 | 12.011 | 6 | 6 | 6 |
| nitrogen | N | 7 | 14.007 | 7 | 7 | 7 |
| oxygen | O | 8 | 15.999 | 8 | 8 | 8 |
| fluorine | F | 9 | 18.998 | 9 | 9 | 10 |
| neon | Ne | 10 | 20.180 | 10 | 10 | 10 |
| sodium | Na | 11 | 22.990 | 11 | 11 | 12 |
| magnesium | Mg | 12 | 24.305 | 12 | 12 | 12 |
| aluminum | Al | 13 | 26.982 | 13 | 13 | 14 |
| silicon | Si | 14 | 28.085 | 14 | 14 | 14 |
| phosphorus | P | 15 | 30.974 | 15 | 15 | 16 |
| sulfur | S | 16 | 32.066 | 16 | 16 | 16 |
| chlorine | Cl | 17 | 35.453 | 17 | 17 | 18 |
| argon | Ar | 18 | 39.948 | 18 | 18 | 22 |
| potassium | K | 19 | 39.098 | 19 | 19 | 20 |
| calcium | Ca | 20 | 40.078 | 20 | 20 | 20 |

Explanation:

1. Element Symbol: These are standard symbols used in chemistry.
2. Atomic Number: Directly taken from the periodic table.
3. Atomic Mass: Also taken from the periodic table. For simplicity, we use the most common isotopic mass.
4. Number of Protons: Equal to the atomic number.
5. Number of Electrons: In a neutral atom, this is equal to the number of protons.
6. Number of Neutrons: Calculated as \( \text{Atomic Mass} - \text{Atomic Number} \). Since atomic mass is not always a whole number, we round it to the nearest whole number.

Final Answer:

\[
\boxed{
\begin{array}{|c|c|c|c|c|c|c|}
\hline
\text{Element Name} & \text{Element Symbol} & \text{Atomic Number} & \text{Atomic Mass} & \text{Number of Protons} & \text{Number of Electrons} & \text{Number of Neutrons} \\
\hline
\text{hydrogen} & \text{H} & 1 & 1.008 & 1 & 1 & 0 \\
\text{helium} & \text{He} & 2 & 4.003 & 2 & 2 & 2 \\
\text{lithium} & \text{Li} & 3 & 6.941 & 3 & 3 & 4 \\
\text{beryllium} & \text{Be} & 4 & 9.012 & 4 & 4 & 5 \\
\text{boron} & \text{B} & 5 & 10.811 & 5 & 5 & 6 \\
\text{carbon} & \text{C} & 6 & 12.011 & 6 & 6 & 6 \\
\text{nitrogen} & \text{N} & 7 & 14.007 & 7 & 7 & 7 \\
\text{oxygen} & \text{O} & 8 & 15.999 & 8 & 8 & 8 \\
\text{fluorine} & \text{F} & 9 & 18.998 & 9 & 9 & 10 \\
\text{neon} & \text{Ne} & 10 & 20.180 & 10 & 10 & 10 \\
\text{sodium} & \text{Na} & 11 & 22.990 & 11 & 11 & 12 \\
\text{magnesium} & \text{Mg} & 12 & 24.305 & 12 & 12 & 12 \\
\text{aluminum} & \text{Al} & 13 & 26.982 & 13 & 13 & 14 \\
\text{silicon} & \text{Si} & 14 & 28.085 & 14 & 14 & 14 \\
\text{phosphorus} & \text{P} & 15 & 30.974 & 15 & 15 & 16 \\
\text{sulfur} & \text{S} & 16 & 32.066 & 16 & 16 & 16 \\
\text{chlorine} & \text{Cl} & 17 & 35.453 & 17 & 17 & 18 \\
\text{argon} & \text{Ar} & 18 & 39.948 & 18 & 18 & 22 \\
\text{potassium} & \text{K} & 19 & 39.098 & 19 & 19 & 20 \\
\text{calcium} & \text{Ca} & 20 & 40.078 & 20 & 20 & 20 \\
\hline
\end{array}
}
\]