Question

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$$\begin{tabular}{|c|c|c|c|c|c|c|} \\hline element & symbol & atomic number & mass number & protons & neutrons & electrons \\\\ \\hline beryllium & be & & 9 & & & \\\\ \\hline \\end{tabular}$$

Explanation:

⚡ Using what you learned: definitions of atomic mass and isotope notation

Step 1: Find the Atomic Number

The atomic number of Beryllium (\(\text{Be}\)) is found on the periodic table.

$$ \text{Atomic Number} = 4 $$

Step 2: Determine Protons and Electrons

For a neutral atom:

$$ \text{Protons} = \text{Atomic Number} = 4 $$

$$ \text{Electrons} = \text{Protons} = 4 $$

Step 3: Calculate Neutrons

Using the mass number given in the table (\(9\)):

$$ \text{Neutrons} = \text{Mass Number} - \text{Protons} $$

$$ \text{Neutrons} = 9 - 4 = 5 $$

Answer:

• Atomic Number: 4
• Protons: 4
• Neutrons: 5
• Electrons: 4