Answer:
This question appears incomplete
Explanation:
This question appears incomplete because of the absence of options. However, hydrogen is placed in group 1 because it has just one electron in it's outermost shell (which happens to be the only shell it has) just like every other group 1A/group 1 element. While helium is placed in group 8A/group 18 because it has a completely filled outermost shell (which is also the only shell it has) just like every other element in group 8A/group 18.
Radioactive isotopes eventually decay, or disintegrate, to harmless materials. Some isotopes decay in hours or even minutes, but others decay very slowly. Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). <u>Plutonium-239 has a half-life of 24,000 years.</u>
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<h3>What is radioactive decay? </h3>
Radioactive decay is the emission of energy in the form of ionizing radiation. The ionizing radiation that is emitted can include alpha particles, beta particles and/or gamma rays. Radioactive decay occurs in unbalanced atoms called radionuclides.
Elements in the periodic table can take on several forms. Some of these forms are stable; other forms are unstable. Typically, the most stable form of an element is the most common in nature. However, all elements have an unstable form. Unstable forms emit ionizing radiation and are radioactive. There are some elements with no stable form that are always radioactive, such as uranium. Elements that emit ionizing radiation are called radionuclides.
Learn more about Radioactive decay
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Answer:
A. wearing sunglasses to to protect eyes from UV rays
Explanation:
Your eyes are outside of your body, meaning external. All the other choices deal with internal organs.
Ocean currents move both warm and cool water across many miles. Warm water can be carried to a cooler place like Alaska. It can bring warmer temperatures as well as warmer water to Alaska. Just like the warm water, cold water can do this as well. If cold water moves from Alaska to The Gulf of Mexico, it can cause the water and air to cool. As air travels over the ocean water vapor can condense into it. The current’s flow depends on what variables are in play. There are many different currents that connect together to heat up and cool off as they move.
Answer:
C.) They have fewer electrons than protons
Explanation:
Charges on ions are determined by the ratio of electrons to protons. Neutral elements have the same number of protons and electrons. Remember: protons have a positive charge and electrons have a negative charge. However, based on the amount of electrons these elements have, some are more or less willing to give up their electrons to participate in ionic bonding. Potassium usually gives up 1 electron because this satisfies the octet rule. By removing this electron, the element has more protons than electrons, giving it an overall +1 charge.
