The metallic character of elements decreases as you move from left to right across a period in the periodic table.

To elaborate, metallic character refers to an element’s tendency to lose electrons and form positive ions, a hallmark of metallic behavior. As one progresses across a period from left to right, the metallic character diminishes. This trend is primarily attributed to an increase in nuclear charge, which draws the electrons closer to the nucleus. Consequently, this increased attraction makes it more challenging for the atom to lose electrons, thereby reducing its metallic character.

At the beginning of a period, alkali metals are present, characterized by their high reactivity and strong inclination to lose electrons. This results in a high metallic character for these elements. As you advance across the period, the elements transition to being less metallic and more non-metallic. This change occurs because the number of protons in the nucleus increases, enhancing the positive charge and further attracting the electrons. As a result, it becomes increasingly difficult for the atom to shed an electron, which is a defining feature of metals.

By the time you reach the end of a period, you encounter the noble gases, which exhibit very low reactivity and a minimal tendency to lose electrons, indicating a low metallic character. In fact, these gases are often referred to as inert gases due to their lack of reactivity. This trend of decreasing metallic character is consistent across all periods within the periodic table.

In summary, as you move from left to right across a period on the periodic table, the metallic character of the elements declines. This decline is driven by the increase in nuclear charge, which pulls electrons closer to the nucleus and makes electron loss more difficult. This pattern is a consistent feature throughout all periods of the periodic table.