1. Identifying the Element:
* Protons determine the atomic number: An atom with 17 protons is chlorine (Cl).
2. Understanding Valence Electrons:
* Valence electrons are in the outermost shell: These are the electrons involved in chemical bonding. Chlorine has 7 valence electrons.
3. Reactivity and the Octet Rule:
* The Octet Rule: Atoms tend to gain, lose, or share electrons to achieve a stable configuration of 8 valence electrons (except for hydrogen and helium, which only need 2).
* Chlorine's Desire for Stability: Since chlorine has 7 valence electrons, it only needs one more to achieve a stable octet. This makes it highly reactive.
4. Chlorine's Reactivity:
* Tendency to Gain Electrons: Chlorine readily gains an electron to form a negatively charged ion (Cl⁻). This makes it a strong non-metal.
* Strong Oxidizing Agent: Chlorine is a strong oxidizing agent, meaning it readily accepts electrons from other atoms. This is why it's used as a disinfectant and bleach.
In summary:
An atom with 17 protons and 7 valence electrons is chlorine. It's highly reactive due to its tendency to gain one electron to achieve a stable octet configuration. This makes it a strong non-metal and a powerful oxidizing agent.
