The half-life of a radioactive compound is the time taken for that said isotope to decay or disintegrate so that only half of the initial atoms remain in that compound. During the decay process, the isotope will give off energy and matter, and the way to depict this is indicated by t 1/2.
Answer:
sodium ,Na and magnesium,Mg
An isotope is when an element has the same number of protons and different number of neutrons. That is why the atomic mass changes.
Best Answer: o.n. = 70 means 70% isoctane for which o.n. = 100 and 30% of heptane for which o.n. = 0
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.
