Answer:
82.4 s
Explanation:
Find the NUMBEr of half lives...then multiply by 54.3
2.27 = 6.5 (1/2)^n
log (2.27/6.5) / log (1/2) = n = 1.52 half lives
1.52 * 54.3 = 82.4 s
Answer:
that's because....
group 1 (e.g Na, K) those tend to lose one electron to gain noble gas electron configuration.
they can achieve that by just losing one electron from their outer shell.
as you go down the group 1, element gets bigger in size, which means there is more space between nucleus (which is in center of atom) and electron of outer shell. the more far away they are the less attraction force between them.
so its easier for potassuim to lose one electron than for lithuim.
so that means potassium will easily give up 1 electron to react with non metal or other element therefore it is more reactive than lithuim
but in case of non metal, the opposite happens but simple to understand.
as you go down the group 7 (halogen- Cl, Br, I) element will get bigger therefore force between nucleus and outer electron is getting smaller. they have to gain 1 electron in order to fill the outer shell (to gain noble gas electron configuration.)
as florine is more smaller in size than clorine it is more reactive because florine has more tendency to pull extra electron from metal or other element towards its side. so it easily gain 1 electron to react.
Answer:
One of the errors for low percentage of magnesium could be because not all the magnesium may have reacted.
Explanation:
During the heating process, if the magnesium have not reacted completely, it can lead to low percentage of magnesium in the oxide formed. The product may still look a bit greyish rather than whitish after the heating process.
Answer: With the exception of hydrogen, all atoms have three main parts. The parts of an atom are protons, electrons, and neutrons. A proton is positively charged and is located in the center or nucleus of the atom. Electrons are negatively charged and are located in rings or orbits spinning around the nucleus.
Explanation:
A chemical change is characterized of the formation of new substances or a chemical reaction. There are a number of observations that we can see if this type of change happens. One would be the formation of gas bubbles, this indicates that one of the products is a gas. Another observation would be a formation of a precipitate in the solution, it would indicate that the new solid formed is not soluble in the solution. A permanent color change in the solution would also indicate a chemical change because it may be that the new substance that is formed has its own distinct color when in solution.
