Answer:
The atomic number of the isotope is reduced by 2 and atomic mass is reduced by 4.
Explanation:
Alpha particle is doubly ionized helium atom. The atomic mass of helium atom is 4 u and atomic number of helium atom is 2. The emission of alpha particle means doubly ionized helium atom will be released from the isotope.
Hence, the emission of the alpha particle will decrease the atomic mass by 4 and atomic number by 2.
Hence, option(a) is correct
Answer:
plusses give me brainliest after this
The answer is: 1. periodic table
Please, observe that it is not right to say that a substance content heat.
Heat is not something that a body or substance content. Heat is the transmission of energy due to difference of temperatures.
An endothermic reactions is that where the reactants abosorb energy from the surroundings to occur. The products, then, will be higher in energy than the reactants while the surroundings get colder.
Answer:
Group 18th
Explanation:
The group 18th of periodic table which is composed of Noble gases mainly was missing from the Mendeleev's periodic table. The reason for this is that Noble gases are least reactive, therefore, it was difficult to predict such elements which do not react with other elements.
