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Answer:
for 17
answer is 7.1 M for preparation of 100 mL solution
Answer:
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Explanation:
16 . step 1
Divide the given percentages of atoms with their molecular masses
H---4.07/1 =4.07
C---24.27/12 =2.02
Cl--71.65/35.5=2.01
step 2
divide all values with the lowest value obtained.
H---4.07/2.01=2
C---2.02/2.01=1
Cl---2.01/2.01=1
therefore the empirical formula is ch2cl
WEIGHT OF EMPIRICAL FORMULA=12+2+35.5=49.5
Given molecular weight =98.96 which is double of empirical weight .therefore molecular formula is c2h4cl2
17. 7.1m
18. The most notable factors affecting the ionization energy include:
1) Electron configuration: this accounts for most element's IE, as all of their chemical and physical characteristics can be ascertained just by determining their respective electron configuration.
2) Nuclear charge: if the nuclear charge (atomic number) is greater, the electrons are held more tightly by the nucleus and hence the ionization energy will be greater.
Number of electron shells: if the size of the atom is greater due to the presence of more shells, the electrons are held less tightly by the nucleus and the ionization energy will be lesser.
3) Effective nuclear charge (Zeff): if the magnitude of electron shielding and penetration are greater, the electrons are held less tightly by the nucleus, the Zeff of the electron and the ionization energy is lesser.[8]
4) Type of orbital ionized: an atom having a more stable electronic configuration has less tendency to lose electrons and consequently has higher ionization energy.
5) Electron occupancy: if the highest occupied orbital is doubly occupied, then it is easier to remove an electron.
Other minor factors include:
1) Relativistic effects: heavier elements (especially those whose atomic number is greater than 70) are affected by these as their electrons are approaching the speed of light, and hence have a smaller atomic radius/higher IE.
2) Lanthanide and actinide contraction (and scandide contraction): the unprecedented shrinking of the elements affect the ionization energy, as the net charge of the nucleus is more strongly felt.
3) Electron pair energies and exchange energy: these would only account for fully filled and half-filled orbitals. A common misconception is that "symmetry" plays a part; albeit, none so far has concluded its evidence.
19 . The spin quantum number describes the spin for a given electron. An electron can have one of two associated spins, (+12) spin, or (−12) spin. An electron cannot have zero spin. We also represent spin with arrows ↑ or ↓. A single orbital can hold a maximum of two electrons and each must have opposite spin.
Magnetic Quantum Number (ml): ml = -l, ..., 0, ..., +l. Specifies the orientation in space of an orbital of a given energy (n) and shape (l). This number divides the subshell into individual orbitals which hold the electrons; there are 2l+1 orbitals in each subshell.
20.
1)They form crystals.
2)They have high melting and high boiling points.
3)They are hard and brittle.
4)They have higher enthalpies of fusion and vapourisation than molecular compounds.
5)They conduct electricity when dissolved in water.
6)ionic solids do not conduct electricity so they are good insulators also.
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