One of the first steps toward currently accepted theories of our solar system's formation and evolution was the general acceptance of the model, which placed the sun at the center of the system and the earth in orbit around it. this theory was prominently presented by

The first blank can be filled with the Heliocentric model, and the second blank can be filled with Copernicus.  

The heliocentric model known as heliocentrism was proposed by the Renaissance astronomer, mathematician, and the Catholic cleric Nicolaus Copernicus resulting in the Copernican revolution.  

It is the astronomical model, in which the planets and the Earth revolve around the Sun positioned at the middle of the Solar system. Factually, the heliocentric model was in contrast to geocentrism, in which Earth is positioned at the center of the Solar system.  

Heliocentric, Nicolaus Copernicus

Explanation:

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it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.