How many valence electrons of oxygen, nitrogen, sodium, chlorine, calcium, bromine, magnesium, iron, silicon, and gold.
The correct answer and explanation is:
Valence Electrons of Common Elements
Here are the valence electrons for the given elements:
| Element | Symbol | Valence Electrons |
|---|---|---|
| Oxygen | O | 6 |
| Nitrogen | N | 5 |
| Sodium | Na | 1 |
| Chlorine | Cl | 7 |
| Calcium | Ca | 2 |
| Bromine | Br | 7 |
| Magnesium | Mg | 2 |
| Iron | Fe | 2 or 3 (variable) |
| Silicon | Si | 4 |
| Gold | Au | 1 or 3 (variable) |
Explanation (300 Words)
Valence electrons are the outermost electrons of an atom and are crucial in determining how an element reacts chemically. They participate in bond formation, either by being shared, gained, or lost.
- Oxygen (O) has 6 valence electrons. It is in Group 16 of the periodic table and needs 2 more electrons to complete its octet, often forming two covalent bonds.
- Nitrogen (N) has 5 valence electrons (Group 15). It tends to form three bonds, commonly seen in compounds like ammonia (NH₃).
- Sodium (Na) has 1 valence electron (Group 1). It easily loses this electron to form a +1 ion, becoming highly reactive.
- Chlorine (Cl) has 7 valence electrons (Group 17). It tends to gain one electron to complete its octet, forming -1 ions or sharing electrons in covalent bonds.
- Calcium (Ca) has 2 valence electrons (Group 2). It loses both to form a +2 ion, typical for alkaline earth metals.
- Bromine (Br), like chlorine, has 7 valence electrons and behaves similarly, forming -1 ions or covalent bonds.
- Magnesium (Mg) also has 2 valence electrons and forms +2 ions upon losing them, commonly found in ionic compounds.
- Iron (Fe) has variable valence electrons (commonly 2 or 3) due to its ability to lose different numbers of d-electrons. This makes iron versatile in forming compounds with different oxidation states.
- Silicon (Si) has 4 valence electrons (Group 14) and can form four covalent bonds, much like carbon.
- Gold (Au) also shows variable valency—typically +1 or +3—because of its electron configuration involving d-orbitals.
Understanding valence electrons is essential in predicting bonding behavior and reactivity across chemical elements.