The answer is D
Calcium has two electrons in its outer energy shell
Answer:
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Explanation:
An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.
2 human activities- wood cutting and roads building.
2 natural events- earthquakesand and flood.
Answer:
A. Iodine
Explanation:
First 2 points describe it's physical properties. Even if we don't remember them, we can easily figure out the answer to be a non-metal. As, non-metals usually have lower bp and mp than metals.
Both Iodine and hydrogen exists as a 2 atom molecule in gas phase.
But only elements of group 17 (halogens) have 7 electrons in their outer shell.
Again, salts are usually ionic compounds, formed by atoms with a greater difference in their electronegativities. Hence, the one that forms bonds with a metal to form a salt readily can be a non- metal.
All these points indicate that the element must be iodine.
Answer:
1.76 g/mL
Explanation:
You need to find the volume. You can do this by subtracting the volume of the water and the rock by the volume of the water.
72.7 mL - 50 mL = 22.7 mL
Now that you have volume, divide the mass by the volume to find the density.
39.943 g/22.7 mL = 1.76 g/mL
