Select the period 2 halogen on the periodic table below.
The correct answer and explanation is:
The period 2 halogen on the periodic table is fluorine (F).
Explanation:
The periodic table is organized in rows called periods and columns called groups or families.
- Periods run horizontally and indicate the number of electron shells an element has.
- Groups run vertically and contain elements with similar chemical properties because they have the same number of electrons in their outermost shell (valence electrons).
Halogens are a group of elements in Group 17 (or Group VIIA) of the periodic table. They are highly reactive nonmetals known for having seven electrons in their outermost shell, which makes them one electron short of a full octet—this leads them to be very reactive as they tend to gain one electron during chemical reactions.
Now, focusing on period 2, which is the second row from the top of the periodic table, the elements there have electrons filling the first and second electron shells. The halogen in this period is the element with 7 valence electrons in the second shell.
- The period 2 elements include: lithium (Li), beryllium (Be), boron (B), carbon (C), nitrogen (N), oxygen (O), fluorine (F), and neon (Ne).
- Among these, only fluorine (F) is a halogen, located in Group 17.
Fluorine is the lightest halogen and is extremely reactive. It forms compounds with almost all other elements and is widely used in industrial applications like producing fluorinated polymers (e.g., Teflon) and in toothpaste as fluoride to prevent dental cavities.
In summary:
- Period 2 halogen = Fluorine (F)
- Located in Period 2 (second row), Group 17 (halogens).
- It has 7 valence electrons and high reactivity.