Which is a true statement? a) a colloidal system does not exhibit the tyndall effect. b) particles can be filtered from a suspension. c) the particles in a colloidal system are affected by gravity. d) a solution is heterogeneous.

B) Particles can be filtered from a suspension.

Explanation: Colloids are solutions with particle size intermediate between true solutions and suspensions. They exhibit tyndall effect that is scattering of light.

Suspensions have large sized particles which settle when left undisturbed for sometime and thus can be filtered off easily.

The particle size in colloids is less and hence they do not settle under the effect of gravity.

A solution can be homogeneous in which the composition is uniform or heterogeneous in which is the composition is not uniform.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

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