•draw lewis dot structures for an atom of each of following elements:
1. k
3. ar
2. si
4.as

Explanation:

Lewis dot structures represent the symbol of an atom we're looking at and the number of valence electrons it has. This number is represented by the sum of dots around the symbol.

Potassium is in group 1A, this means it only has one valence electron, so we draw K with one dot in its Lewis diagram;Argon is in group 8A, this means it has eight valence electrons, so we draw Ar with 8 dots around it in its Lewis diagram;Silicon is in group 4A, this means it has four valence electrons, so we draw Si with 4 dots around it in its Lewis diagram;Arsenic is in group 5A, this means it has five valence electrons, so we draw As with 5 dots around it in its Lewis diagram.

Those are represented in the image attached below:

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water