Question

what is the atomic number for iron (fe)?
○ 80
○ 45
○ 26
○ 2

how many valence electrons do elements in group 2 (alkaline earth metals) have?
○ 1
○ 2
○ 3
○ 4

what is the trend in reactivity as you move from left to right across the periodic table?
○ reactivity stays the same
○ reactivity increases only
○ reactivity generally decreases

Explanation:

First Question: Atomic number of Iron (Fe)

The atomic number of an element is the number of protons in its nucleus, and it's a unique identifier for each element. Iron (Fe) has an atomic number of 26. The options 80 (mercury), 46 (palladium), and 2 (helium) are incorrect.

Elements in Group 2 of the periodic table have 2 valence electrons. This is a fundamental property of this group; they tend to lose these 2 electrons to form +2 ions. So the correct answer is 2.

For metals (left side), reactivity decreases as we move right across a period (due to increasing ionization energy). For non - metals (right side), reactivity generally increases but overall, when considering the whole period from left to right, reactivity generally decreases (since the left - most metals are very reactive and as we move right, metallic reactivity drops, and non - metallic reactivity increase starts from a lower base). The option "Reactivity generally decreases" is correct. "Reactivity stays the same" is wrong as reactivity changes across the table. "Reactivity increases only" is wrong as metals become less reactive as we move right.

Answer:

26 (assuming the option with 26 is one of the choices, likely the third option as per the given choices: 80, 46, 26, 2)

Second Question: Valence electrons in Group 2 (Alkaline Earth Metals)