If the stigma is messed up it is hard for bees or insects to pollinate because the way they pollinate is by eating the nectar from the stigma and stick the pollen on their body and stick it on the stigma.
But if there is no stigma=no pollination
A good example of a model is a lily
Answer:
1 and 2
Explanation:
when we r adding chlorine to water
the water is clean
Answer:
Group 2A (or IIA) of the periodic table are the alkaline earth metals: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). They are harder and less reactive than the alkali metals of Group 1A.
Explanation:
Answer:
Explanation:
Actinoids are the series have 15 element in the periodic table.
Chemistry of actinoids are complicated because of the following reasons.
- Their outer most orbitals are 6d and 7s but most of the electrons resides in 5f orbitals. These orbitals are most exposed to environment and incoming electron picked up by 5f orbital instead of 6d or 7s orbitals.
- They are radioactive elements that couldn't be handle in normal condition to study their properties.
- Their f-orbital can accommodate 14 electrons and they have many variable oxidation state.
- 5d electron donot contribute in the formation of chemical bonds.
- They have a very strong tendency to make complexes
- Most of the actinoides are artificial and are in very minute in amount. they are in very less quantity that is amounts found in nano-grams so are more expensive too and
- As they are radioactive so their half life is very short and in very less time the decay occur so couldn't be study as upon decay their actual properties changed.
Due to all the above reasons it make difficult for a chemist to study about the chemical properties of actinoids.
