Answer:
3)alpha decay because alpha particles have two protons and two neutrons
Explanation:
When a radioactive isotope undergoes a decay, a daughter nucleus or nuclei is/are formed. The mass number and atomic number of the daughter nucleus gives us an idea of the nature of radioactive decay that the parent nucleus underwent.
If the daughter mass number of the daughter nucleus is four units less than that of the parent nucleus and the atomic number of the daughter nucleus is two units less than that of the parent, then such a decay is an alpha decay.
An alpha particle has two protons and two neutrons thus it has a mass number of 4 and an atomic number of two.
Answer:
there is no chance of any defects. 2) The position of isotopes becomes clarified in modern periodic table. That is the main two reasons as to why modern periodic table is less defective than Mendeeleev's periodic table.
Explanation:
Reason 1:- It is based on atomic number.
Reason 2:-Problem regarding Position of isotopes is resolved.
Reason 3:-Problem of position of Cobalt and Nickel is resolved whigh were placed wrongly in mandeelev periodic table.
Reason 4:-Blank spaces which were there in mandeelev periodic table are no more vacant now.
Answer:
A potentiometric pH meter is used to measure the pH of a solution.
Explanation:
A pH meter is an common instrument that is used to measure the hydrogen-ion concentration in aqueous solutions , the meter indicates its acidity or alkalinity and is expressed as pH.
The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is often called a potentiometric pH meter. The difference in electrical potential is related to the pH of the solution.
Potentiometric pH meters consists of a simple electronic amplifier and a pair of electrodes, alternatively it may consist of a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested and pH values are read off.
Question 17
The subscript 2 is the atomic number for helium and subscript 4 is the mass number for Helium
<u><em>explanation</em></u>
when writing down an isotope of an element the mass number of that isotope is written in upper side of the chemical symbol, while atomic number is written on the lower side.
Since 4 is on upper side it is the mass number of He, while 2 is the atomic number since it is on lower side.
Question 18
The type of radiation emitted when polonium -212 form lead 208 is an alpha particle
<u><em>explanation</em></u>
Alpha decay is a decay in which an atomic nuclei emit an alpha particles and be transformed into different atomic nuclei with a mass number that is reduced by 4
polonium 212 is reduced by 4 to form lead 208 therefore it undergo alpha particle decay.
