Pointâofâsale transactionsâi.e., swiping a card at the time of purchaseâsecurely encrypt the. credit card data. Cards placed on file for future transactions, such as for express checkâout, use. tokens to access card data.
The outermost layer of Earth is the atmosphere. I say the atmosphere is the outermost layer, because it is as much a part of the of our planet as the atmosphere of other planets is a part of their definition.
An outermost shell has no more than 8 electrons (2 in the s orbital and 6 in the three p orbitals) because after the s and p subshells are full, adding another electron will start filling the s subshell of the next shell farther out, which then becomes the outermost shell. http://en.wikipedia.org/wiki/Auf...