Hydrogen can be placed in group `17` of the periodic table because

Options

A. hydrogen forms hydrides like `NaH`
B. hydrogen has isotopes `D` and `T`
C. it is light
D. hydrogen combines with halogens

Answer

To answer the question "Hydrogen can be placed in group 17 of the periodic table because," we need to analyze the properties of hydrogen and how they relate to the elements in group 17, which are the halogens. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understand the Position of Hydrogen
- Hydrogen is the first element in the periodic table with an atomic number of 1. Its electronic configuration is 1s¹.

### Step 2: Compare Electronic Configurations
- Group 17 elements (halogens) have electronic configurations that are one electron short of a noble gas configuration. For example, fluorine has the configuration 1s² 2s² 2p⁵, needing one more electron to achieve the stable configuration of neon (1s² 2s² 2p⁶).
- Hydrogen, with its 1s¹ configuration, also needs one additional electron to achieve a stable configuration similar to helium (1s²).

### Step 3: Electronegativity
- Hydrogen has a relatively high electronegativity, similar to the halogens. This means hydrogen can attract electrons effectively, which is a characteristic of halogens.

### Step 4: Oxidation States
- Hydrogen can exhibit an oxidation state of -1, similar to halogens. For example, in hydrogen halides (like HCl), hydrogen acts like a halogen by gaining an electron.
- Additionally, hydrogen can also exhibit a +1 oxidation state when it forms compounds with metals (like NaH).

### Step 5: Formation of Compounds
- Hydrogen can form covalent compounds similar to halogens. For example, it can form methane (CH₄), just as halogens can form compounds like carbon tetrachloride (CCl₄).

### Conclusion
Based on these comparisons, hydrogen can be placed in group 17 due to its electronic configuration, electronegativity, oxidation states, and its ability to form covalent compounds similar to halogens.

### Final Answer
Hydrogen can be placed in group 17 of the periodic table because it has an electronic configuration that allows it to gain one electron, it exhibits similar electronegativity and oxidation states as halogens, and it can form covalent compounds like halogens.

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