Question

1. choose the best answer. atomic numbers __ across a period and down the periodic table. increase; increase decrease; increase decrease; decrease increase; decrease 14) choose the best answer. atomic masses across a period and __ down the periodic table. increase; decrease increase; increase decrease; increase decrease; decrease

Explanation:

The atomic number is the number of protons in an atom's nucleus. As we move across a period (left - to - right) and down a group (top - to - bottom) in the periodic table, the number of protons increases, so the atomic number increases. Atomic mass is the sum of protons and neutrons. Generally, as we move across a period and down a group, the number of protons and neutrons increases, leading to an increase in atomic mass.

Answer:

1. A. increase; increase
2. B. increase; increase