Two electrons.
Yes, calcium is defined as a metal because of both its physical and chemical traits. They all have an outer shell with two electrons and are very reactive. Those elements in the second column have two electrons ready to make compounds. It shouldn't surprise you that calcium has a valence of 2.
Answer:
True
Explanation:
The value of the mole is equal to the number of atoms in exactly 12 grams of pure carbon-12. 12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms • The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 1023).
Answer: B) Electromagnetic waves can travel through empty space.
Explanation:
Conduction: This type of heat transfer happens when there is direct contact between the two object. Example: heating a pan on stove.
Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas) due to the movement of hot layers to the top and cold layers to the bottom which leads to convection currents. Example: Heating of swimming pool.
Radiation: This type of heat transfer happens when there is direct transfer of energy through empty space.The electromagnetic radiation from the surface of an object which is due to the object's temperature is radiation. Example: Heating of earth's surface.
Answer:
Air is mostly gas
The air in Earth's atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen. Air also has small amounts of lots of other gases, too, such as carbon dioxide, neon, and hydrogen.
Explanation:
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