Opposite pairs form ionic bonds, due to this the answer is D - Li and Br; They have unlike charges.
At an oceanic/oceanic plate boundary 2 oceanic plates will collide against each other. The older oceanic plate will sub-duct under the newer one. It will sub-duct into magma, and will melt into it. The plate and magma will create a reaction, and will build up pressure. With enough pressure, magma will erupt creating a volcano.
To answer this problem, we need to count the electrons in the given configuration. The complete configuration is 1s2 2s2 2p6 3s2 3p6. There are 2+2+6+2+6 equal to 18 electrons. We find next the element with an atomic number of 18. That element is noble gas argon.
Answer:contains 2 atoms of Fe and 3 atoms of oxygen. Total of 5 atoms in a single molecule