Answer: The statement is true
Explanation:
The half-life of a radioactive isotope is the time taken for half of the total number of atoms in a given sample of the isotope to decay.
For instance
The half-life of radium is 1622 years. This means that if we have 1000 radium atoms at the beginning, then at the end of 1622 years, 500 atoms would have disintegrated, leaving 500 undecayed radium atoms
Thus, the statement is true
Answer is: an instant ice pack becoming cold, splitting a gas molecule and baking bread.
<span>Endothermic reaction
is chemical reaction that absorbs more energy than it releases.
</span>In ice pack, <span>reaction absorbs heat from the surroundings (endothermic reaction), lowering the surrounding temperature.
For splitting molecule and baking bread we must add energy to break bonds between atoms.</span>
Answer: O potássio possui apenas um elétron de valência. ... Considerando que o cálcio possui dois elétrons de valência, requer mais energia para a remoção de um elétron de valência. Devido a esse potássio, é mais reativo que o cálcio.
Explanation:
Simple molecules have no overall charge, or charged particles that can separate, so simple molecular substances cannot conduct electricity, even when liquid or dissolved in water.
