Answer: Chemical change
Explanation:
Physical change is a change in which there is no rearrangement of atoms and thus no new substance is formed. There is only change in physical state of the substance. The change can be reversed using physical methods.
Chemical change is a change in which there is rearrangement of atoms and thus new substance is formed. There may or may not be a change in physical state. The change can only be reversed using chemical methods.
Thus when iron and sulfur are heated in a test tube, the chemical change occurs and thus lead to formation of new substances which could not be separated using magnet.
Lithium is a good reducing agent because it is electropositive [it rapidly gains electrons]
fluorine is good oxidizing agent electronegative [it loses electrons fastly]
Charcoal with a carbon-14 activity of 0.60 compared to new wood has less than 5,730 years.
<h3>What is a radioactive isotope?</h3>
A radioactive isotope is an element in nature that emit radioactivity in a given period of time (e.g., the half-life for C14 is equal to 5,730 years).
Radioactive dating is a technique to measure the age of an element by measuring its radioactive activity.
In conclusion, charcoal with a carbon-14 activity of 0.60 compared to new wood has less than 5,730 yr.
Learn more about radioactive dating here:
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In general, The more valence electrons a metal has, the stronger its metallic bonds will be because Boron is a metalloid and is ionically bonded.it is too electronegative to release its valence electrons for metallic bonding.As a result, their valence electrons feel a stronger pull from the nucleus (a greater effective nuclear charge) and are less easily released for metallic bonding.
I believe those all look correct!
