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>
Answer:
When a wave is present in a medium (that is, when there is a disturbance moving through a medium), the individual particles of the medium are only temporarily displaced from their rest position.
Explanation:
Answer:
See explanation
Explanation:
In an atom, the inner electrons may shield the outer electrons from the attractive force of the nucleus. We, refer to this phenomenon as the <u><em>shielding effect</em></u>, It is defined as a decrease in the magnitude of attraction between an electron and the nucleus of an atom having more than one electron shell (energy level).
Shielding effect increases down the group due to addition of more shells but decreases across the period due to the increase in the size of the nuclear charge.
As the magnitude of shielding increases down the group, ionization of electrons becomes easier and the first ionization energies of elements decreases as we move down the group. Since shielding effect decreases across the period, the first ionization energies of elements increases across the period.
Carbon disulfide is prepared by heating sulfur and charcoal. the chemical equation is S2(g) + C(s) <---> CS2 (g) Kc = 9.40 at 900 K.
Hope this helps:)
