The valency of an element with atomic number 13 is:
A. 2
B. 3
C. 4
D. 1
Answer: Option B
Solution (By JKExamLibrary)
The element with atomic number 13 is Aluminum. Its electronic configuration is 2, 8, 3. Since it has 3 electrons in its outermost shell, it loses these 3 electrons to achieve a stable octet configuration, making its valency 3. It forms Al³⁺ ions in chemical compounds.
Explanation:
Red litmus turning blue indicates that the solution is basic. Basic solutions have a pH greater than 7. Among the options, 10 is the only value greater than 7. pH 1 and 4 are acidic (turn blue litmus red), and 7 is neutral (no change in litmus color).
Explanation:
Methanol (CH₃OH) contains the hydroxyl (–OH) functional group characteristic of alcohols. It is the simplest alcohol, also called wood alcohol. Ethanol (C₂H₅OH) is the alcohol in beverages. Aldehydes have –CHO group, ketones have >C=O, carboxylic acids have –COOH. Methanol is toxic; ingestion can cause blindness or death. It is used as a solvent and in formaldehyde production.
Explanation:
Atomic number 11 is sodium (Na). The electron shells fill as 2 in K, 8 in L, and the remaining 1 in M. Thus configuration is 2,8,1. It belongs to Group 1 (alkali metals) and Period 3. The configuration determines its valency (1) and reactivity.
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