Answer:
Refer to your periodic table. Lewis dot structures are based off the number of valence electrons an atom has.
Looking at the compounds, we can see that Gallium has three valence electrons in its outer shell and oxygen has six. Oxygen and Gallium are going to share electrons with one another, making a V shape in their diagram.
One Oxygen would make a double bond with a Gallium, leaving one valence electron to another oxygen. That oxygen takes that Final electron. It now has 7 in its outer shell. The remaining Gallium and Oxygen do the same double bond as the one before, leaving the 7 valence electron oxygen with one more electron.
a) Group 2 elements have 2 electrons on their outer shell, so they form a 2+ charge.
b) they lose 2 electrons as they are transferred to the non metal.
c)They obtain this charge as when they are made into an ionic compound the 2 electrons on the outer shell are transferred to the non metal, meaning there are 2 more protons that electrons, giving it a positive charge.
hope this helps! :)
Answer: Seastars prey on mussels and shellfish which would otherwise have no other natural predators. Herbivorous fish like the butterflyfish pictured to the left prey on marine algae. Without this crucial predator-prey balance, the algae would over-grow, which would then kill coral, as they compete for the same resources.
Radioisotopes are widely used to diagnose disease and as effective treatment tools. For diagnosis, the isotope is administered and then located in the body using a scanner of some sort.
