The periodic table is arranged according to several trends. Which of the following is true as you move from left to right along the periodic table:
A the element's atomic mass decreases and the atomic number increases
B the element's productivity increases
C the element's reactivity decreases as it's stability increases
D the atomic number increases as the reactivity increases****
Correct.
http://edtech2.boisestate.edu/lindabennett1/502/periodic%20table%20e%20config/PTable_trends%20around%20table.html
To determine which of the given options is true as you move from left to right along the periodic table, you need to understand the trends in atomic mass, atomic number, productivity, reactivity, and stability.
A) The element's atomic mass decreases and the atomic number increases: This statement is not true. As you move from left to right along the periodic table, the atomic number increases, but the atomic mass generally increases as well. Atomic mass is primarily determined by the sum of protons and neutrons in an atom's nucleus.
B) The element's productivity increases: The concept of productivity is not directly related to the arrangement of elements in the periodic table. Productivity refers to a measure of output efficiency or the rate at which work is done, which is unrelated to the properties of elements.
C) The element's reactivity decreases as its stability increases: This statement is also not true. As you move from left to right across the periodic table, the general trend is that the elements become less reactive and more stable. This is because elements on the left side of the periodic table tend to be more metallic and readily give up electrons to form positive ions, whereas elements on the right side are more non-metallic and tend to gain electrons to form negative ions. So, as you move from left to right, reactivity generally decreases and stability increases.
D) The atomic number increases as the reactivity increases: This statement is the correct answer. As you move from left to right along the periodic table, the atomic number increases. The atomic number represents the number of protons in the nucleus of an atom, which also determines the element's identity. Additionally, as mentioned earlier, reactivity generally decreases from left to right, meaning that elements towards the left side of the periodic table are more reactive than those on the right.
Therefore, option D is the correct answer: The atomic number increases as the reactivity increases as you move from left to right along the periodic table.