The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers. This was proposed by Henry Moseley, correcting Mendeleev's periodic table which was based on atomic mass. Atomic number determines the electronic configuration and thus chemical properties.
Explanation:
Sodium carbonate (soda ash) is dissolved in water and crystallized to obtain washing soda. Heating baking soda gives anhydrous sodium carbonate. Brine electrolysis gives NaOH, Cl₂, H₂. Solvay process makes Na₂CO₃.
Explanation:
Neutron has mass approximately equal to proton (1.675 × 10⁻²⁷ kg) and no electric charge. Proton mass ~1.673 × 10⁻²⁷ kg, positive charge. Electron mass ~9.11 × 10⁻³¹ kg, negative charge. Positron is the antiparticle of electron, same mass, positive charge. Neutron's neutrality makes it important for nuclear stability.
Explanation:
Fertilizer grade is expressed as N-P₂O₅-K₂O percentage by mass. So 15-15-15 means 15% N, 15% P₂O₅ (not elemental P), and 15% K₂O (not elemental K). To convert P₂O₅ to P, multiply by 0.44; K₂O to K by 0.83. This is a balanced compound fertilizer providing all three primary macronutrients.
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