Elements occur naturally in different forms called isotopes. These are the same atoms with the same number of protons but has different number of neutrons. Almost all elements exist in nature as such. The amounts of these isotopes are expressed in terms of percent abundances and since it is in a percentage units, the sum of all the abundances should equate to 100 percent or else the calculation is wrong. This is not true onlt for magnesiun but with all of the elements. The atomic mass of these elements also depends on the percent abundances of the isotopes since it is a weighted average value of the individual masses of the isotopes.
Answer:
a lithium atom (Z=3, A=7 AMU) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).
Explanation:
Answer:
Physical change is the change that you can see like for example if you turn your light on and off thats physical (thats the best definition for that i can do) and also physical change can go back to its original form it was before. A chemical change is when you do something to something and it cannot be changed back to its original form. Like for example, if you bake a pie, you cannot un-cook all the ingredients to make it raw again
Explanation:
learned this in 5th grade
Hence they got seven electrons in ground state
Answer:
C. The rate of the reaction begins to decrease as the reactants are used.
Explanation:
a p 3 x
