The reactivity of elements in the periodic table does not follow a simple pattern solely based on atomic number or atomic mass. Here's a breakdown of your questions:
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Does an element's reactivity decrease along with its atomic number?
- This is not generally true. Reactivity can vary significantly across periods and groups regardless of atomic number. For instance, alkali metals (group 1) become more reactive as you move down the group, despite increasing atomic numbers.
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Does an element's reactivity decrease as atomic mass increases?
- This is also not a consistent trend. While heavier elements can sometimes be less reactive, many factors influence reactivity, including electronic configuration and the specific properties of the element. For example, many of the heaviest noble gases are quite unreactive, but some heavy transition metals can be quite reactive.
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Does an element's reactivity decrease from left to right on the periodic table?
- Generally, this is more applicable to metals and nonmetals. For metals, reactivity tends to decrease from left to right across a period (e.g., alkali metals are very reactive while transition metals are less so). However, for nonmetals, reactivity tends to increase from left to right; for example, halogens (group 17) are very reactive, with reactivity increasing as you move across the group.
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Does an element's reactivity decrease from right to left on the periodic table?
- This describes a trend that can apply to nonmetals across a period but is not a solid rule for all elements. Nonmetals on the right side of the periodic table (like the halogens) are highly reactive, and as you move to the left, the elements become less reactive. However, it doesn't apply universally to all groups, especially since metals are generally more reactive as you move down a group.
In summary, reactivity in the periodic table is influenced by various factors, including atomic structure and bonding characteristics, and does not follow straightforward trends based purely on atomic number, atomic mass, or horizontal or vertical positioning on the table.