All categories

2 years ago

Which number indicates the energy level of an atom's valence electrons?

Chemistry

1 answer:

In-s [12.5K]2 years ago

3 0

Answer:

The group number

Explanation:

For the main group elements which are those in groups 1A, 2A, and 3A-8A (skipping the transition elements) the digit that goes with the group number is also the number of valence electrons. (Group 1A elements have one valence electron, Group 2A have 2, and so on.)

You might be interested in

Be sure to answer all parts. The percent by mass of bicarbonate (HCO3−) in a certain Alka-Seltzer product is 32.5 percent. Calcu

pochemuha

Answer : The volume of $CO_2$ will be, 514.11 ml

Explanation :

The balanced chemical reaction will be,

$HCO_3^-+HCl\rightarrow Cl^-+H_2O+CO_2$

First we have to calculate the mass of $HCO_3^-$ in tablet.

$\text{Mass of }HCO_3^-\text{ in tablet}=32.5\% \times 3.79g=\frac{32.5}{100}\times 3.79g=1.23175g$

Now we have to calculate the moles of $HCO_3^-$ .

Molar mass of $HCO_3^-$ = 1 + 12 + 3(16) = 61 g/mole

$\text{Moles of }HCO_3^-=\frac{\text{Mass of }HCO_3^-}{\text{Molar mass of }HCO_3^-}=\frac{1.23175g}{61g/mole}=0.0202moles$

Now we have to calculate the moles of $CO_2$ .

From the balanced chemical reaction, we conclude that

As, 1 mole of $HCO_3^-$ react to give 1 mole of $CO_2$

So, 0.0202 mole of $HCO_3^-$ react to give 0.0202 mole of $CO_2$

The moles of $CO_2$ = 0.0202 mole

Now we have to calculate the volume of $CO_2$ by using ideal gas equation.

$PV=nRT$

where,

P = pressure of gas = 1.00 atm

V = volume of gas = ?

T = temperature of gas = $37^oC=273+37=310K$

n = number of moles of gas = 0.0202 mole

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get :

$(1.00atm)\times V=0.0202 mole\times (0.0821L.atm/mole.K)\times (310K)$

$V=0.51411L=514.11ml$

Therefore, the volume of $CO_2$ will be, 514.11 ml

6 0

2 years ago

Give Me a simple definition for Acids.

levacccp [35]

Answer:

an acid is a substance which produces hydrogen ions as the only as the only positive ion when dissolved in water.

8 0

1 year ago

Aluminum has a face-centered cubic unit cell. How many atoms of Al are present in each unit cell

Serjik [45]

Answer:4

Explanation:

As shown in the image attached, a face-centred cubic structure has 8 atoms at the corners and 6 face center atoms.

Each corner atom contributes to eight cell, so per unit cell 1/8 ×8 =1atom

Face center atoms contributes to two unit cells 1/2 × 6=3atoms

Total atoms =3+1=4atoms

Therefore the atoms in Al FCC per unit cell is 4

7 0

3 years ago

3) How many moles of solute are dissolved in 1.5 L of a 0.80 M solution? * 10 points

Mrrafil [7]

Answer:

1.2

Explanation:

Molarity = moles/volume

to find the moles, you must multiply both sides by volume

so, take 1.5 L * 0.80 M

this equals 1.2 :)

7 0

2 years ago

How did oxygen first enter Earth's atmosphere?

forsale [732]

Answer:

I think c biological processes

8 0

2 years ago