The length of time required for half of the radioactive atoms in a sample to decay is its <span>half-life. The correct option among all the options that are given in the question is the first option or option "A". The other choices are incorrect and can be easily neglected. I hope that this is the answer that has come to your help.</span>
Answer:
Fossil fuels.
Explanation:
A fossil fuel is a fuel obtained from nature such as crude oil, coal, wood etc. The burning of fossil fuels releases tremendous amounts of carbon IV oxide into the environment causing a myraid of environmental problems paramount among them is global warming with its attendant consequences.
Answer:
8 electrons
Explanation:
Magnesium is present on group 2.
It has 2 valence electrons.
Electronic configuration of magnesium:
Mg₁₂ = 1s² 2s² 2p⁶ 3s²
1st energy level contain 2 electrons.(1s²)
2nd energy level contain 8 electrons. (2s² 2p⁶)
3rd energy level contain 2 electrons. (3s²)
3rs energy level of magnesium is called valence shell. It contain two valance electrons. Magnesium can easily donate its two valance electrons and get stable electronic configuration.
It react with halogens and form salt. For example,
Mg + Cl₂ → MgCl₂
The best answer is the isotope of strontium which is strontium-85. It has a half-life of about 64 days. The metal strontioum has four stable, naturally occurring isotopes which includes 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%).
