What is the difference between a group and a period in the periodic table?
The Correct Answer and Explanation is:
Correct Answer:
In the periodic table, a group is a vertical column, while a period is a horizontal row.
Explanation:
The periodic table of elements is organized to reflect recurring trends in the properties of elements. It is divided into vertical columns called groups and horizontal rows called periods.
Groups run from top to bottom. There are 18 groups in the modern periodic table. Elements within the same group have the same number of valence electrons, which are the electrons in the outermost energy level. Because of this, elements in the same group often exhibit similar chemical properties. For example, all elements in Group 1 (also known as the alkali metals) are highly reactive metals and form similar compounds. The reactivity of metals in a group typically increases as you move down the column.
Periods run from left to right across the table. There are 7 periods in the periodic table, each corresponding to a principal energy level being filled with electrons. As you move across a period from left to right, the number of protons in the nucleus increases by one with each step, and electrons are added to the same outer shell. This causes a gradual change in properties. For example, atomic size generally decreases from left to right across a period, while electronegativity and ionization energy tend to increase.
In summary, groups organize elements with similar chemical behavior due to their similar outer electron configurations, while periods show trends in properties as the number of electrons and protons increases. Understanding the difference between groups and periods is essential for predicting element behavior and for understanding trends in reactivity, atomic size, and bonding patterns across the periodic table.
