Question

Which pair has both members from the same period of pcriodic tablc? (1) \(\mathrm{Mg}, \mathrm{Ba}\) (2) \(\mathrm{Mg}, \mathrm{Na}\) (3) \(\mathrm{Mg}, \mathrm{Cu}\) (4) \(\mathrm{K}, \mathrm{Cl}\)

Short answer

Pair (2) Mg and Na are from the same period (Period 3).

Step-by-step solution

- Identify Periods

Check the periodic table to identify which period each element belongs to. Recall that periods are the horizontal rows of the periodic table.

- Determine Period for Each Element

Determine the period for the given elements: Mg (Magnesium) is in Period 3, Ba (Barium) is in Period 6, Na (Sodium) is in Period 3, Cu (Copper) is in Period 4, K (Potassium) is in Period 4, and Cl (Chlorine) is in Period 3.

- Compare Element Pairs

Compare the periods of elements in each pair: (1) Mg (P3) and Ba (P6) — Different periods, (2) Mg (P3) and Na (P3) — Same period (Period 3), (3) Mg (P3) and Cu (P4) — Different periods, (4) K (P4) and Cl (P3) — Different periods.

- Conclusion

Determine which pair has both elements in the same period. From the comparisons, the pair (Mg, Na) has both elements in Period 3.

Key concepts

Element Periods

Periods in the periodic table are horizontal rows. Elements in the same period have the same number of electron shells. For example, Period 1 has just two elements: Hydrogen and Helium, both having one electron shell.
Identifying the period of an element helps understand its properties and behaviors. Magnesium (Mg) and Sodium (Na), for instance, both belong to Period 3, indicating they have the same number of electron shells. However, Barium (Ba) is in Period 6, showing it has more electron shells, resulting in different chemical and physical characteristics.

Periodic Table Analysis

The periodic table is organized in a way that reflects the structure of atoms. It consists of rows (periods) and columns (groups) where each element is positioned based on its atomic number. This organization helps us predict the elements' chemical behavior and properties.

When analyzing elements like Magnesium (Mg) and Copper (Cu), you can see that Mg is in Period 3 and Cu is in Period 4. By knowing this, we can infer that Copper has an additional electron shell compared to Magnesium. Such analysis is crucial for understanding how elements interact in chemical reactions.

Comparing elements based on their periodic placement allows us to identify patterns and relationships between different chemical elements. This systematic approach provides a visual and logical framework for studying chemistry.

Chemical Elements Identification

Identifying chemical elements involves understanding their position in the periodic table and recognizing their symbols. Each element has a unique atomic number and elemental symbol, such as Mg for Magnesium and Na for Sodium.

Steps for Identifying Elements:

• Check the atomic number, which represents the number of protons in an element.
• Use the periodic table to find the element's symbol and position.
• Notice the element’s period and group, which provide information about its electron configuration and common properties.

For example, identifying Magnesium (Mg) involves finding its position in Period 3 and Group 2. This tells us Mg has three electron shells and is an alkaline earth metal, influencing its reactivity and bonding behavior.
Understanding these basics aids in deciphering complex chemical reactions and properties of substances involved.