What is the central atom of H2O?

Water has 4 regions of electron density around the central oxygen atom (2 bonds and 2 lone pairs). These are arranged in a tetrahedral shape. The resulting molecular shape is bent with an H-O-H angle of 104.5°.

Explanation:

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c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.