Which of the following statements is not correct regarding hydrogen:

Options

A. It resembles halogens in some properties
B. It resembles alkali metals in some properties.
C. It can be placed in `17^(th)` group of Modern periodic table.
D. It cannot be placed in `1^(st)` group of Modern periodic table.

Answer

To determine which statement is not correct regarding hydrogen, we will analyze each of the four statements provided.

**Step 1: Analyze Statement 1**
- Statement: "It resembles halogens in some properties."
- Analysis: This statement is correct. Hydrogen has similar properties to halogens, such as its ability to gain an electron to achieve a noble gas configuration (1s²) and its similar electronegativity. Hydrogen can form diatomic molecules (H₂) like halogens (e.g., Cl₂).

**Step 2: Analyze Statement 2**
- Statement: "It resembles alkali metals in some properties."
- Analysis: This statement is also correct. Hydrogen has one electron in its outer shell (1s¹), similar to alkali metals. It can lose this electron to form H⁺, just like sodium (Na) can lose its outer electron to form Na⁺.

**Step 3: Analyze Statement 3**
- Statement: "It can be placed in the 17th group of the modern periodic table."
- Analysis: This statement is correct. Hydrogen can form hydrides (e.g., NaH) similar to how alkali metals form halides (e.g., NaCl). It shares some properties with group 17 elements, such as forming ionic and covalent bonds.

**Step 4: Analyze Statement 4**
- Statement: "It cannot be placed in the first group of the modern periodic table."
- Analysis: This statement is not correct. Hydrogen can indeed be placed in the first group of the periodic table due to its electronic configuration (1s¹) and its ability to exhibit a +1 oxidation state, similar to alkali metals.

**Conclusion:**
The statement that is not correct regarding hydrogen is Statement 4. Therefore, the answer is option D.

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