Explanation:
Fertilizers are chemically synthesized plant nutrients.
Nitrogen (N), Phosphorus (P) and Potassium (K) are macronutrients and are required in large amounts by plants. So, farmers use fertilizers in order to supply these nutrients. NPK 15:15:15 , NPK 20:20:20, NPK 15:30:15 are examples of fertilizers used to supply N, P, K to crops.
Molarity is expressed as the number of moles of solute per volume of the solution. For example, we are given a solution of 2M NaOH this describes a solution that has 2 moles of NaOH per 1 L volume of the solution. Acids and bases can be measured through the concentrations of H+ and OH- ions in units of molarity. Hope this helps.
1) ₁₄Si 1s²2s²2p⁶3s²3p².
Principal quantum number (n=3) have four electrons (3s²3p²).
2) ₁₉K 1s²2s²2p⁶3s²3p⁶4s¹.
Azimuthal quantum number (l=o) have seven electrons (1s²2s²3s²4s¹).
3) ₈₀Hg [Xe] 4f¹⁴5d¹⁰6s².
Principal quantum number (n=4) have thirty-two electrons (4s²4p⁶4d¹⁰4f¹⁴).
The principal quantum number<span> is one of four </span>quantum numbers<span> which are assigned to each electron in an </span>atom<span> to describe that electron's state.</span>
The azimuthal quantum number<span> is a </span>quantum number<span> for an </span>atomic orbital<span> that determines its </span>orbital angular momentum<span> and describes the shape of the orbital. </span>
Part (a):
Chalk has the chemical formula: CaCo₃
From the periodic table:
mass of Ca = 40 grams
mass of Co = 58.9 grams
Therefore:
molecular weight of chalk = 40 + 3(58.9) = 216.7 grams
Part (b):
Advantages of M<span>andeleev's periodic table:
1- Could predict the properties of elements easily based on its position in the periodic table
2- Elements were arranged systematically in order of increasing atomic mass which helped in the study and classification of elements
3- Even after the discovery of noble gases, no major changes needed to be done to the periodic table. Noble gases were inserted easily
4- He left room for other undiscovered elements based on his systematic approach in writing the table
Hope this helps :)</span>
