HALOGENS have 7 electrons in their final shell regardless if the total number of atoms. These 7 electrons would be shared between the 's' and 'p' orbital in the form
ns² np⁵ (the same as the question). Attached is a table that highlights the fact that halogens have the same form in terms of the valence electrons.
CO2
The symbol how you write
Apple snails inhabit a wide range of ecosystems from swamps, ditches and ponds to lakes and rivers. The majority of the species prefer lentic water above streaming water and only a few species have adapted to rivers with strong current.
<span>Breathing through the siphon when submerged (<span>Pomacea canaliculata</span>).</span>
The lung/gills combination in apple snails reflects their adaptation to habitats with oxygen poor water. This is often the case in swamps and shallow waters. The without thelung they would completely depend on their gills, which would decrease their ability to survive.
Another advantage of air breathing in combination with a shell door (operculum) is the ability to survive periods of drought often common in these habitats during the dry season.
You should first count all the valence electrons. Then draw the central atom and single bonds to the rest (then go from there)
For this problem, let's use the approach of dimensional analysis. This technique is done by cancelling out like units that appear both on the numerator and the denominator side. As a result, this technique will let you know that your final answer conforms to what parameter is asked. In this case, the final answer should be in mL. The solution is as follows:
14.5 mg * 1 mL/25 mg = 0.58 mL