Answer:
merits of mendeleev periodic table are:
- it was first scientific and systamatic study of different element.
- there were may gaps for in discovered elements.After their discovery the got their proper place in table.
- with the help of mendeleev periodic table , properties of several elements were studied correctly.
demerits of mendeleev periodic table
- it could not arrange hydrogen as it shows the property of both alkali and halogens.
- it could not arrange isotopes because they have different atomic weight but same atomic number.
- it could not arrange Lanthanides and Actinides.
hope these points helped you
need more points then comment it .
2250cm3= 2250/1000000m3=.00225m3
Answer:
Got your back
Explanation:
If the ions derived from different atoms are isoelectronic species, then they all have same number of electrons in their electronic shells and will have got same electronic configuration but their nuclear charge will differ because of their difference in number of protons in the nucleus. With increase in number of protons in the nucleus the electrons are more attracted towards nucleus thereby causing the decrease in ionic radius. On this principle our problem will be solved
The given ions are
7N-3
→no. of proton
=7
and
no of electron
=10
8O-2
→
no. of proton
=8
and
no of electron
=10
9F-→
no. of proton=9
and no of electron=10
11Na→
no. of proton=11
and no of electron=10
12 Mg-3→
no. of proton=12 and
no of electron=10
Hence the increasing order of ionic radius is
12Mg-3<11Na+<9F-<8O-2<7N-3
To rmember ->For isoelectronic species lower the nuclear charge higher the radius
Answer:
A. Soaps react with ions in hard water to create a precipitate.
B. Soaps are both hydrophobic and hydrophilic.
D. Soaps should be weakly alkaline in solution.
Explanation:
A. Hard water contains <u>magnesium and calcium minerals</u> like calcium and magnesium carbonates, sulfates and bicarbonates. As soon as these minerals come in contact with soap their ions like Mg²⁺ & Ca²⁺ form precipitates.
B. Soap are both hydrophilic and hydrophobic. They reason why they exhibit both the properties is really important for their functionality. The hydrophobic part of soap makes interaction with oil/dust particles while the hydrophilic part makes interaction with water. When the cloth is rinsed the dirt/soap particles are removed from the dirty clothes thereby making them clean.
C. Soaps have alkaline pH i.e. more than 7 that is why they have bitter taste.
Surface area<span> of a solid object is a measure of the total </span>area<span> that is occupied by the surface of object.
If two objects has same mass, then smaller size particles will have greater surface area.
Thus, in order to increase the surface area of ice, one can crush it into small particles. Due to crushing, particles will break into smaller size and eventually this will result in larger surface area. </span>
