Because its a synthetic element.
The number that appears in brackets is the most stable isotope of technetium.
Because its a Synthetic Element!!!!!!!!
The standardized atomic weight of technetium is [98] amu.
why is the atomic mass of technitium usually in brackets?
Probably because technetium does not occur naturally; all its isotopes are radioactive with short half-lives compared with naturally occurring radioactive elements such as uranium.
because it is an isotope???
All isotopes of technetium are radioactive. Technetium is found only in trace quantities in nature, and then usually only in certain ores where it is a product of radioactive decay. All of the technetium used is synthetic.
Usually only in a laboratory; technetium is an artificial element that does not occur in nature.
Usually, brackets are used to organize a league's playoff games.
a low-level radioactive marker, usually technetium-99m or technetium pertechnetate.
Brackets are a way of ordering the priority of operations. In mathematics, usually things with brackets have their operations completed first.
Parentheses are usually placed inside brackets.
The different types of brackets are:round brackets, open brackets or parentheses: ( )square brackets, closed brackets or box brackets: [ ]curly brackets, squiggly brackets, swirly brackets, braces, or chicken lips: { }angle brackets, diamond brackets, cone brackets or chevrons: < > or ⟨ ⟩Parentheses (singular, parenthesis)---sometimes called round brackets, curved brackets, oval brackets, or just brackets, or, colloquially, parens --- contain material that could be omitted without destroying or altering the meaning of a sentence. Example: Sometimes I like to use parenthesis (they make everything more fun).Square brackets are mainly used to enclose explanatory or missing material usually added by someone other than the original author, usually in quoted text. Example: I appreciate it [the honor], but I must refuse.Curly brackets (also called braces, or "squiggly brackets") are sometimes used in prose to indicate a series of equal choices. Example: Select your animal {goat, sheep, cow, horse} and follow me.Angle brackets are often used to enclose highlighted material. Some dictionaries use angle brackets to enclose short excerpts illustrating the usage of words.An example can be:I used the brackets to mark off important information in my research paper.