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.
The reaction includes the single replacement reaction and redox
<h3>Further explanation</h3>
Single replacement : one element replaces another element in a compound
A + BC ⇒ AC + B
The oxidation-reduction reaction or abbreviated as Redox is a chemical reaction in which there is a change in oxidation number
3CuCl + 2Al => 3Cu + 2AlCl₃
Al replacing Cu in the CuCl compound
3Cu²⁺ + 6e⁻⇒ 3Cu reduction(oxidation number from +2 to 0)
2Al⇒2Al³⁺+6e⁻ oxidation(oxidation number from 0 to +3)
Answer:
magnesium
Explanation:
magnesium has fewer valence shells meaning that the protons have a stronger hold on the electrons and it would take more energy to remove an electron to create an ion.
<u>Answer:</u>
<em>1) ∆H is positive 
Endothermic
</em>
<em>2) 
Endothermic </em>
<em>3) Energy is absorbed Endothermic
</em>
<em>4) 
Exothermic
</em>
<em>5) ∆H is negtive Exothermic
</em>
<em></em>
<u>Explanation:</u>
∆H is called as enthalpy change
It is also called as Heat of reaction
Energy is required for the bond to break a bond.
Energy is released when a bond is formed.
that is
We see in this equation, bonds between hydrogen and chlorine molecules gets broken and on the right side bond is formed in HCl.
If energy of products greater than energy of reactants then the reaction enthalpy change is endothermic .
If energy of products lesser than energy of reactants then the reaction enthalpy change is exothermic .
For example
(positive hence endothermic)
(negative hence exothermic)
Such high amounts of pressure cause this layer to remain in a _____solid_____ state of matter even though the nickel and iron are at such a high temperature.
