The atomic number of an element is determined by the number of:
A. Neutrons
B. Protons
C. Electrons
D. Nucleons
Answer: Option B
Solution (By JKSSB Mock Tests)
Atomic number (Z) is the number of protons in the nucleus, which defines the identity of the element. In a neutral atom, the number of electrons equals Z. Neutrons contribute to mass number but not atomic number. Isotopes have same Z but different number of neutrons. Nucleons are total protons + neutrons = mass number. The modern periodic table is based on atomic number.
Explanation:
Distilled water is considered the purest form of water because it is obtained by boiling water and condensing the steam, leaving almost all impurities, minerals, and salts behind. Rainwater is relatively pure but dissolves atmospheric gases and dust as it falls.
Explanation:
Haematite (Fe₂O₃) is a major ore of iron. Bauxite is aluminium ore, galena is lead sulfide, cinnabar is mercury sulfide. Magnetite (Fe₃O₄) is another iron ore.
Explanation:
Bronze is an alloy primarily of copper and tin, sometimes with other elements. Brass is Cu-Zn. Steel is Fe-C. Duralumin is Al-Cu-Mg-Mn. Bronze is used for statues, coins, and bearings.
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