Because the calcium ion donates two electrons to achieve the stable state. So the layer of electrons decrease form 4 layers(2,8,8,2) to 3 layers(2,8,8). Thus, the radius of a calcium ion is smaller than a calcium atom.
A and d is physical, b and c is chemical
Answer:
atmosphere
Explanation:
The atmosphere absorbs the most in light because the atmosphere surrounds our planet
Answer:
I will give up the electrons
Explanation:
Consider the following rules:
1. An atom loses electrons if its oxidation number is positive.
2. An atom gains electrons if its oxidation number is negative.
3. An atom neither gains nor loses electrons if its atomic number is zero.
As I have an oxidation number 
that is oxidation number is positive, so, I will give up electrons.
Large minerals are created from magma, when magma rises to the Earth's surface it cools slowly. As the magma cools, solid rocks form. Rocks are mixtures of minerals. Granite is a common rock that forms when magma cools. It contains the minerals quartz, plagioclase feldspar, and potassium feldspar. The different colored speckles in the granite are the crystals of the different minerals. The mineral crystals are large enough to see because the magma cools slowly, which gives the crystals time to grow.
Small minerals are created from lava, since lava is on the Earth's surface so it cools quickly compared to magma on Earth. Hence, rocks form quickly and mineral crystals are very small. Sometimes, lava cools so hastily that crystals cannot form at all, forming a black glass called obsidian. Because obsidian is not crystalline, it is not a mineral.
NOTE: Minerals (and gems) are crystals.
