A casualty is the damage, destruction, or loss of property resulting from an identifiable event that is sudden, unexpected, or unusual. 1  A sudden event is one that is swift, not gradual or progressive. 2  An unexpected event is one that is ordinarily unanticipated and unintended.
exists and is an alternate of . The noble gas notation is a notation formed as a result of the electron configuration notation being used in conjunction with noble gases. The noble gas preceding the element in question is written then the electron configuration is continued from that point onwards. The notation is shorter to write and makes it easier to identify elements.
An element's noble gas shorthand notation makes use of the electron configuration of the noble gas that comes immediately before the element in the periodic table. Start by writing the complete electron configuration of boron, B. Boron is located in period 2, group 13, and has an atomic number equal to 5. This means that the electron configuration of a neutral boron atom must account for a total of 5 electrons. The complete electron configuration for a boron atom will look like this B:  1s^2 2s^2 2p^1 Now, the noble gas that comes immediately before boron in the periodic table is located in period 1, group 18, and it's called helium, He.