HELP QUICK I HAVE A QUIZ ITS JUST MULTIPLE CHOICE

If an atom has a mass number of 25 and an atomic number of 11 how many neutrons are there in this atom?

babunello [35]

C. 14
you would subtract the mass number from the protons or the atomic number because in order to find the mass number you would add the protons and neutrons :)

5 0

3 years ago

Group 7A (17) elements can gain one electron to attain a noble gas electron configuration. In combination with metal atoms that

Iteru [2.4K]

Answer:

The two statements are all True for group 7 and 8 elements.

Explanation:

The Group 7 elements are known as the halogens. They are reactive non-metals and are always found in compounds with other elements. Chlorine, bromine and iodine are all halogens.

Chlorine, bromine and iodine are the three common Group 7 elements. Group 7 elements form salts when they react with metals. The term ‘halogen’ means 'salt former'.

In addition to the discription given to norble gases in the question which is true, norble gases;

are inert gases located on the right of the periodic table.

have a full-set of valence electrons, so they're stable, unreactive

are colorless, odorless and tasteless.

have low melting and low boiling points.

can be found in small amounts in the Earth's crust and the Earth's atmosphere.

5 0

3 years ago

The differences between two molecules include the type of sugar that forms a section of the molecules and the identity of one of

klio [65]

The answer is nucleic acids

3 0

3 years ago

When a 2.00 g sample of KCl is dissolved in water in a calorimeter that has a total heat capacity of 1.28 kJ ⋅ K − 1 , the tempe

Alchen [17]

Answer : The molar heat of solution of KCl is, 17.19 kJ/mol

Explanation :

First we have to calculate the heat of solution.

$q=c\times (\Delta T)$

where,

q = heat produced = ?

c = specific heat capacity of water = $1.28kJ/K$

$\Delta T$ = change in temperature = 0.360 K

Now put all the given values in the above formula, we get:

$q=1.28kJ/K\times 0.360K$

$q=0.4608kJ=460.8J$

Now we have to calculate the molar heat solution of KCl.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 460.8 J

m = mass of $KCl$ = 2.00 g

Molar mass of $KCl$ = 74.55 g/mol

$\text{Moles of }KCl=\frac{\text{Mass of }KCl}{\text{Molar mass of }KCl}=\frac{2.00g}{74.55g/mole}=0.0268mole$

Now put all the given values in the above formula, we get:

$\Delta H=\frac{460.8J}{0.0268mole}$

$\Delta H=17194.029J/mol=17.19kJ/mol$

Therefore, the molar heat of solution of KCl is, 17.19 kJ/mol

7 0

3 years ago

What kind of electrical charges do protons,electrons, and neutrons have?

Vinil7 [7]

Protons = Positive Charge

Neutrons = Neutral Charge/No Charge

Electrons = Negative Charge

This one's simple: electrons have a negative charge, protons have a positive charge and neutrons — as the name implies — are neutral.

Protons

Elements are differentiated from each other by the number of protons within their nucleus. For example, carbon atoms have six protons in their nucleus. Atoms with seven protons are nitrogen atoms. The number of protons for each element is known as the atomic number and does not change in chemical reactions. In other words, the elements at the beginning of a reaction -- known as the reactants -- are the same elements at the end of a reaction -- known as the products.

Neutrons

Although elements have a specific number of protons, atoms of the same element may have different numbers of neutrons and are termed isotopes. For example, hydrogen has three isotopes, each with a single proton. Protium is an isotope of hydrogen with zero neutrons, deuterium has one neutron, and tritium has two neutrons. Although the number of neutrons may differ between isotopes, the isotopes all behave in a chemically similar manner.

Electrons

Electrons are not bound as tightly to the atom as protons and neutrons. This allows electrons to be lost, gained or even shared between atoms. Atoms that lose an electron become ions with a +1 charge, since there is now one more proton than electrons. Atoms that gain an electron have one more electron than protons and become a -1 ion. Chemical bonds that hold atoms together to form compounds result from these changes in the number and arrangement of electrons.

4 0

3 years ago