(a) Does metallic character increase, decrease, or remain unchanged as one goes from left to right across a row of the periodic table? (b) Does metallic character increase, decrease, or remain unchanged as one goes down a column of the periodic table?

Verified step by step guidance

1. Step 1: Understand the concept of metallic character. Metallic character refers to the tendency of an element to lose electrons and form positive ions (cations). Elements with high metallic character are typically good conductors of electricity and heat, have a shiny appearance, and are malleable and ductile.
2. Step 2: Analyze the trend across a period (row) in the periodic table. As you move from left to right across a period, elements generally become less metallic. This is because the number of protons in the nucleus increases, which leads to a stronger attraction between the nucleus and the electrons, making it harder for the atoms to lose electrons.
3. Step 3: Analyze the trend down a group (column) in the periodic table. As you move down a group, the metallic character generally increases. This is because the atomic size increases, and the outer electrons are further from the nucleus, which reduces the effective nuclear charge experienced by these electrons, making it easier for the atoms to lose electrons.
4. Step 4: Relate these trends to specific examples. For instance, in the second period, lithium (Li) is more metallic than beryllium (Be), and in the alkali metal group, lithium (Li) is less metallic than cesium (Cs).
5. Step 5: Summarize the trends. Across a period, metallic character decreases from left to right. Down a group, metallic character increases. These trends are due to changes in atomic size and effective nuclear charge.