The family on the periodic table that has a filled outer
energy level is VIIIA. The answer is letter D. They are also called the noble
gases or inert gases. They are virtually unreactive towards other elements or
compounds. They are found in trace amounts in the atmosphere. Their elemental form
at room temperature is colorless, odorless and monatomic gases. They also have
full octet of eight valence electrons in their highest orbitals so they have a
very little tendency to gain or lose electrons to form ions or share electrons with
other elements in covalent bonds.
The water gets cold because the ice cube is endothermic. Which means it takes in heat. It takes the warmth from the water and melts the ice cube which the ice cube releases coldness which cools down the water.
1) Left up: a chemical change. We can see new substance (red-blue) is formed from one blue and one red atom.
In chemical change new substances are formed, the atoms are rearranged and the reaction is followed by an energy change.
2) Left down: a chemical change. We can see new substance (red-blue) is formed from two blue and one red atoms.
3) MIddle: a physical change. There is no new substance. Bonds are not broken.
4) Right up: a chemical change. Bonds are broken.
5) Right down: a physical change. Change of state of matter.
