<u>Answer:</u> The correct answer is isotopes generally have the same chemical properties, but often different nuclear properties.
<u>Explanation:</u>
Isotopes are defined as the chemical species of the same element which have same atomic number but differ in their mass number.
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons
Nuclear properties of an element is determined by the number of protons and neutrons present in a nucleus.
Chemical properties of an element is determined by the number of electrons present in an atom.
Isotopes have same atomic number, this means that they have same number of protons and electrons but they differ in mass number, which means that they differ in number of neutrons.
Hence, isotopes will have same chemical properties but different nuclear properties.
The valence electron does the halogens possess are 7
- Valence electrons are found in the outermost energy level of an atom
- They are involved in the formation of chemical bonding with other atoms.
- The halogens elements are found in group 17 on the periodic table
- The halogens include fluorine, chlorine, bromine, iodine and astatine.
- They have seven valence electrons, so they are extremely reactive as they only need one more to fill their outer shell.
- By octet rule we can say that the electron with 8 outer most shell is full and stable.
Hence the halogens posses 7 valence electron
Learn more about the valence electron on
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Answer:
It's the third option.
Explanation:
In order for the chemical equation to be correctly it needs the same number of atoms of each element on both sides of the equal sign
Answer:
The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol
Explanation:
The ∆H (heat of reaction) of the combustion reaction is the heat that accompanies the entire reaction. For its calculation you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient (number of molecules of each compound that participates in the reaction) and finally subtract them:
Enthalpy of the reaction= ΔH = ∑Hproducts - ∑Hreactants
In this case, you have: 2 NOCl(g) → 2 NO(g) + Cl₂(g)
So, ΔH=
Knowing:
- ΔH= 75.5 kJ/mol
- = 90.25 kJ/mol
- = 0 (For the formation of one mole of a pure element the heat of formation is 0, in this caseyou have as a pure compound the chlorine Cl₂)
- =?
Replacing:
75.5 kJ/mol=2* 90.25 kJ/mol + 0 -
Solving
-=75.5 kJ/mol - 2*90.25 kJ/mol
-=-105 kJ/mol
=105 kJ/mol
<u><em>The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol</em></u>
Answer:
1. Hot air is less dense then cold air therefore it is lighter the cold air. Because the hot air is less dense it helps lift the balloon up and because cold air is more dense it is heavier and helps the balloon slowly drop the balloon.
To be honest I don't know what 2 is but hope this helps some!