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Explorit Science Challenge #27

Question #1 - The nucleus of an atom is a dense mass of nuclear particles of energy including protons and neutrons. This part of the atom is usually very stable and unchanging. The particles of an atom that are involved when chemical reactions occur between substances, are the negatively charged particles in orbit around the nucleus.

Question: What are the negatively charged particles of an atom called?
Names of those with correct responses


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Question #2 - Some atomic nuclei including those of isotopes of uranium, carbon-14 and strontium-90 are not stable. These atoms spontaneously disintegrate over varying periods of time. Some take billions of years to disintegrate and some only a few seconds. Scientists can measure the rate of decay of such unstable nuclei but because individual nuclei of a particular element decay at slightly different rates the measurements involve the overall rate of decay of the nuclei in a collection of atoms of an element. The measurement is defined as the time it takes for a specific proportion of the nuclei in a sample to decay.

Question: When measuring the rate of decay of an unstable atomic nucleus, what is the specific proportion (of a sample of the atoms) used by scientists - is it one quarter, one third or some other fraction of the sample?

Names of those with correct responses

Question 1. Correct answer received from: Becca W. Youth, Leah, BAM, Courtney, df, Nelda, Joelle (Youth), Sam, Malibu, Jay, Diane, Beth Bemis, Morganaus Starr, nix, jgm. Stacey47, Stickwoman, Sky, Cassie, Toby, Wayne, Amanda, Faye Ng (Youth).
Question 2. Correct answer received from: Becca W. Youth, Leah, BAM, Courtney, df, Nelda, Sam, Malibu, Jay, Diane, Beth Bemis, Morganaus Starr, Darci, jgm. Stacey47, Sky, Toby, Wayne, Amanda, Faye Ng (Youth).

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