To find out how electrons are arranged in an element, you can use the periodic table. It might seem tricky at first, but it's pretty straightforward once you understand how the table works.

Elements are lined up by their atomic numbers. This number tells you how many protons and usually electrons (in a neutral atom) are in that element. Let's break it down into simple steps:

Step 1: Check the Element’s Atomic Number

• The atomic number is the number at the top of each box in the periodic table.
• For example, oxygen (O) has an atomic number of 8. This means it has 8 electrons.

Step 2: Learn About Electron Shells

• Electrons are found in shells around the center of the atom, called the nucleus.
• The first shell can hold 2 electrons.
• The second shell can hold 8 electrons.
• The third shell can also hold 8 electrons, but it can fit more if the atom is bigger.

Step 3: Fill the Shells Following the Rules

• Start adding electrons from the lowest shell (closest to the nucleus) to the highest.
• You fill the first shell, then the second shell, and so on.
• For example, with oxygen's 8 electrons, you would arrange them like this:
  • First shell: 2 electrons
  • Second shell: 6 electrons

Step 4: Write the Electron Configuration

• The way we write the electron arrangement is usually short and simple.
• For oxygen, it looks like this: $1s^2 2s^2 2p^4$.
  • $1s^2$ means there are 2 electrons in the first shell.
  • $2s^2$ means there are 2 electrons in the second shell's special area (s orbital).
  • $2p^4$ means there are 4 electrons in the second shell's other area (p orbitals).

Conclusion

Using the periodic table like this helps you see how electrons are arranged in an element. Once you practice a bit, you'll start noticing patterns that connect different elements. Enjoy your exploration!