Alpha particles. Alpha particles are made of 2 protons and 2 neutrons. This means that they have a charge of +2, and a mass of 4. (the mass is measured in atomic mass units, where each proton & neutron=1) We can write them as , or, because they're the same as a helium nucleus, . Alpha particles are relatively slow and heavy.
For more, visit TIME Health. 1  The average attention span for the notoriously ill-focused goldfish is nine seconds, but according to a new study from Microsoft Corp., people now generally lose concentration after eight seconds, highlighting the affects of an increasingly digitalized lifestyle on the brain.
Related words. 1  span verb. 2  attention span noun. 3  spick and span adjective.  1. the amount of time that something lasts Nearly 100 witnesses testified over a span of 20 days. attention/concentration span (=the period for which you can pay attention/concentrate): Kids these days have a very limited attention span.