The question asks about the placement of hydrogen in the periodic table, considering its dual behavior. We need to analyze the properties of hydrogen and compare them with alkali metals (Group 1) and halogens (Group 17) to determine its appropriate position.
B) Separately, at the top, without being strictly assigned to Group 1 or Group 17. This option correctly reflects the unique position of hydrogen due to its resemblance to both alkali metals and halogens, making it difficult to place definitively in either group.
The question asks to identify which group of elements shares a structural feature with hydrogen, specifically existing as a diatomic molecule (\(H_2\)). We need to recall the common forms in which elements from each given group exist.
A) Halogens — Halogens (e.g., \(F_2\), \(Cl_2\), \(Br_2\), \(I_2\)) exist as diatomic molecules, similar to hydrogen (\(H_2\)). They are non-metals that form covalent bonds to achieve a stable electron configuration.
The question asks to identify which group of elements shares the physical state property of existing as a gas at ordinary room temperature with hydrogen. This requires knowledge of the common physical states of different element groups at room temperature (approximately 20-25 °C).
Correct Option: A) Halogens (e.g., Cl2, F2)
Hydrogen exists as a diatomic gas (\(\text{H}_2\)) at ordinary room temperature. Among the given options, the halogens (Group 17) include fluorine (\(\text{F}_2\)) and chlorine (\(\text{Cl}_2\)), both of which are diatomic gases at room temperature. This makes them share the physical state property with hydrogen.
The question asks to characterize hydrogen at room temperature, contrasting it with Group 1 metallic solids. We need to recall the properties of hydrogen and its classification in the periodic table.
Correct Option: B) Non-metallic gas
The question asks about the possible oxidation states of hydrogen. To answer this, we need to recall the chemical properties of hydrogen, specifically its electronegativity and how it forms bonds with different types of elements (metals and non-metals).
Correct Option: C) Both +1 and −1
To determine which noble gas the hydride ion (H⁻) is isoelectronic with, we need to compare their electron configurations. Isoelectronic species have the same number of electrons. We will calculate the number of electrons in H⁻ and then find the noble gas with that same number of electrons.
A) Helium has 2 electrons, which is the same number of electrons as the hydride ion (H⁻).