The mystery element that remains solid at room temperature and also breaks very easily is a : Non-metal ( B )
A non metal is non conducting element at room temperature, which can be in gas, sold and liquid forms at room temperature, when in solid form they can break easily and do not bend as well. Non-metals are poor conductors of heat and electricity therefore will not conduct electricity when placed in a circuit. An example of a solid non-metal is Carbon.
Hence we can conclude that the mystery element is a Non-metal
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