Answer: D) helium.
Explanation:
Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.
Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.
Example: 
Thus when deuterium and tritium , the two isotopes of hydrogen are fused, a heavier nuclei helium is being formed from two smaller nuclei releasing a neutron.
Reactivity of non-metals depend on their ability to gain electrons. So, smaller is the size of a non-metal more readily it will attract electrons because then nucleus will be more closer to valence shell. ... Hence, Br is the non-metal which will be more reactive than At.
According to Kepler's second law of orbital motion, a plane's orbital speed changes , depending on how far it is from the sun. The closer a planet is to the sun, the stronger the sun's gravitational pull on it, and the faster the planet moves. The farther away from the sun, the weaker the sun's gravitational pull and the slower it moves in its orbit.
The orbit of a planet around the sun is not a perfect circle, but an ellipse - a flattened circle.
Answer:The number of atoms in 2.0 mole Al is A. 2.0 Al atoms. B. 3.0 x 1023 Al atoms.
Secondly, is aluminum an atom or molecule? Aluminum is the second element in the thirteenth column of the periodic table. It is classified as a post-transition metal and a "poor metal". Aluminum atoms contain 13 electrons and 13 protons. There are 3 valence electrons in the outer shell.
