Helium - 4 isotope has 2 protons and 2 neutrons.
Its atomic number is 2 (the number of protons). Atomic number is the number of protons in the atom of an element and it identifies the element. All the isotopes of an element have the same atomic number (same number of protons). So, all the isotopes of hellium have 2 protons.
The number 4 that identifies the helium - 4 isotope is the mass number, i.e. the number of protons plus the number of neutron. So, helium-4 isotope has 2 protons and 2 neutrons. While, other isotopes of helium have 2 protons but different number of neutrons.
The atomic number enable us to deduce the number of electrons in an atom because the atoms are neutral, which implies that the positive and negative charge are equal. Given that the magnitude of the charge of electons and protons are equal but the sign is opposed (protons are positve and electrons are negative) the number of electrons in the atom equals the number of protonts. That is why the atomic number is also the number of electrons of the atom.
Answer: The decay energy is the energy released by a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation.
The answer is C. Glue gun melts a glue stick.
1.806x10^24
Written equation form(always start the equation off with what you know based off of the question!):
3mol(CCl4)•6.022x10^23/1mol = 1.806x10^24
Good luck!
Answer:
4. 1; 6; 2 — synthesis
Explanation:
<u>Decomposition reaction </u>is defined as the reaction in which a single large substance breaks down into two or more smaller substances.
<u>Single displacement </u>reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.
The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.
<u>Synthesis reaction</u> is defined as the reaction in which smaller substances combine in their elemental state to form a larger substance.
The unbalanced combustion reaction is shown below as:-
On the left hand side,
There are 4 phosphorus atoms and 1 calcium atom
On the right hand side,
There are 2 phosphorus atoms and 3 calcium atoms
Thus,
Right side, 
must be multiplied by 2 to balance phosphorus.
Left side, 
is multiplied by 6 so to balance the whole reaction.
Thus, the balanced reaction is:-
Thus, answer:- 4. 1; 6; 2 — synthesis
