In a hydrogenation reaction, a catalyst is used to transform an to an

In  a hydrogenation   reaction  a  catalyst  is  used  to  transform  an   alkene  to  alkane.  Hydrogenation  is  a  chemical  reaction  involve  chemical  reaction  between  molecular  hydrogen  and  another  compound  or   element  in   a  presence  of  catalyst  such  as nickel,  palladium  or  platinum. The  reaction  involve  breaking  of  carbon-carbon  double  bond  in  alkene in  presence  of  catalyst.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

explanation

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

Ok so co(g) is not pronoused that. the only clue is that youpronouse it the oppisote way.