What period are the following elements in?
a. He c. Rb b. Ge d. I
The correct answer and explanation is:
Here are the periods for the given elements:
- He (Helium): Period 1
- Ge (Germanium): Period 4
- Rb (Rubidium): Period 5
- I (Iodine): Period 5
Explanation:
The periodic table is organized in rows called periods and columns called groups or families. Elements in the same period have the same number of electron shells. The period number corresponds to the highest energy level of the electrons in that element.
- Helium (He) is in Period 1 because it is the second lightest element after hydrogen, with only two electrons occupying the 1st energy level. The first period consists of only hydrogen and helium, which are the simplest and lightest elements.
- Germanium (Ge) is in Period 4, located in the p-block. It has four electron shells, with its outermost electrons in the 4th energy level. Germanium is a metalloid, and it lies in the same group as carbon and silicon, which are also in Period 4.
- Rubidium (Rb) is in Period 5. It is an alkali metal found in the 1st group. Rubidium has five electron shells, with its outermost electrons in the 5th shell. Alkali metals are highly reactive and share similar properties, such as having one electron in their outermost shell.
- Iodine (I) is in Period 5 as well. It is a halogen, found in Group 17, and shares Period 5 with elements like bromine and selenium. Iodine has five electron shells, with the outermost electrons in the 5th shell. Halogens are known for their reactivity, especially in forming salts with metals.
The periodic table arranges elements based on their atomic number and properties, helping predict their behavior based on their period and group.