What Elements that have an atomic number less than 37 and atomic mass greater than 78.4u?

Write the chemical symbols for three different atoms or atomic cations with 27 electrons. asap!

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

Complete the sentence. the lower the hydrogen ion concentration, the the ph. higher lower closer to 7 closer to 0