Determine Atomic Mass Group and State of Monoatomic Anion

To find the atomic mass, group in the periodic table, and physical state at room temperature of the element $\text{A}$, we analyze the given properties of its monoatomic anion $\text{A}^-$:

1. Number of Protons and Atomic Number ($Z$): The anion $\text{A}^-$ has a net charge of $-1$ and contains $36$ electrons. $\text{Number of electrons in neutral atom } \text{A} = 36 - 1 = 35$ Since the neutral atom is electrically neutral, the number of protons (atomic number, $Z$) is: $Z = 35$ The element with atomic number $Z = 35$ is Bromine ($\text{Br}$).

2. Atomic Mass ($A$): The atomic mass (mass number) is the sum of the number of protons and neutrons: $\text{Atomic Mass } (A) = \text{Protons} + \text{Neutrons} = 35 + 45 = 80$

3. Group in the Periodic Table: The electronic configuration of the element with $Z = 35$ is: $1\text{s}^2 2\text{s}^2 2\text{p}^6 3\text{s}^2 3\text{p}^6 3\text{d}^{10} 4\text{s}^2 4\text{p}^5$ Since the valence shell configuration is $4\text{s}^2 4\text{p}^5$, it is a p-block element. $\text{Group Number} = 10 + \text{valence electrons} = 10 + (2 + 5) = 17$

4. Physical State at Room Temperature: Bromine ($\text{Br}_2$) exists as a liquid at room temperature.

Thus, the atomic mass, group in the periodic table, and physical state at room temperature are 80, 17, and liquid respectively.

Correct Option: A