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4 years ago

Beryllium (Be): 1sC2sD, what's C and D?

Chemistry

2 answers:

zheka24 [161]4 years ago

3 0

C=2
D=2
the correct ansssssssssssswwwwwwwwwwwwwweeeeeeeeeeeeeerrrrrrrrrrrr
answer

Deffense [45]4 years ago

3 0

Answer:

C is equal to 2 and D is equal to 2.

Explanation:

Here C and D represents number of electrons in 1s and 2s orbitals.

Be has 4 electrons. Now, in order write electronic configuration of an atom, electron filling should be started from orbital with lowest energy.

Energy order of orbital with increasing energy: 1s< 2s< 2p< 3s< 3p< 4s< 3d....

So, filling of electron should start from 1s orbital then 2s, 2p, 3s, 3p and so on.

Each orbital can have maximum of 2 electrons.

So electronic configuration of Be is: $1s^{2}2s^{2}$

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One atom of silicon can properly be combined in a compound with

julia-pushkina [17]

Answer:

C. two atoms of oxygen.

Explanation:

Step 1: Data given

Silicon has 14 electrons

Silicon is part of Group IV, all the elements there have 4 valence electrons.

It can form a compound when 4 valence electrons bind with the 4 valence elctrons of silicon

A. four atoms of calcium.

Calcium has 2 valence elctrons. 4 atoms of calcium cannot bind on 1 atom of silicon since there are only 4 valence electrons.

B. one atom of chlorine.

1 atom of chlorine has 7 valence electrons. Chlorine can bind with an atom with 1 valence electron. Since silicon has 4 valence electrons, they will not bind.

Silicon can bind with 4 atoms of chlorine to form SiCl4

C. two atoms of oxygen.

Oxygen has 6 valence electrons, this means oxygen can bind with an element with 2 valence electrons.

Since silicon has 4 valence electrons, it can bind with 2 atoms of oxygen to form SiO2 (silicon dioxide).

D. three atoms of hydrogen.

Hydrogen has 1 valence electron. 1 hydrogen atom can bind with an element that has 7 valence electrons.

Three atoms of hydrogen can bind with an element that has 5 valence electrons.

Silicon will not bind with 3 atoms of hydrogen ( but can bind with 4 atoms of hydrogen)

5 0

4 years ago

What volume would 3.01•1023 molecules of oxygen gas occupy at STP?

Sliva [168]

First, find moles of oxygen gas: (3.01 x10^23 molec.)/(6.02 x10^23) =0.5mol O2

Second, multiply moles by the standard molar volume of a gas at STP:(0.5mol)(22.4L) = 11.2L O2

6 0

3 years ago

AL2(SO4)2.XH2O has 8.1% aluminium by mass.The value of X ?

In-s [12.5K]

Answer:

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Explanation:

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2 years ago

Calculate to three significant digits the density of chlorine pentafluoride gas at exactly and exactly . You can assume chlorine

slega [8]

Answer:

Density is 6.16g/L

Explanation:

... at exactly -15°C and exactly 1atm...

Using general gas law:

PV = nRT

We can find density (Ratio of mass and volume) in an ideal gas as follows:

P/RT = n/V

To convert moles to grams we need to multiply the moles with Molar Weight, MW:

n*MW = m

n = m/MW

P/RT = m/V*MW

P*MW/RT = m/V

Where P is pressure: 1atm;

MW of chlorine pentafluoride: 130.445g/mol

R is gas constant: 0.082atmL/molK

And T is absolute temperature: -15°C+273.15 = 258.15K

Replacing:

P*MW/RT = m/V

1atm*130.445g/mol / 0.082atmL/molK*258.15K = m/V

6.16g/L = m/V

<h3>Density of the gas is 6.16g/L</h3>

7 0

3 years ago

What is a valence electron

shtirl [24]

is an outer shell electron that is associated with an atom

3 0

4 years ago