Hydrogenous sediments originate from elements in?

Match each object to its description: a. coma of a comet b. comet tail c. oort cloud haze surrounding a nucleus created by solar wind. hypothetical sphere around the solar system

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below. potassium (k): 1s22s22p63s23p64s1