1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
pychu [463]
3 years ago
9

Which element does X represent in the following expression: 2512X?

Chemistry
2 answers:
pogonyaev3 years ago
8 0
<span>I bet this is the notation used in nuclear reactions. The superscript represents the mass number while the subscript represents the atomic number of the element X. So, we find the element with an atomic number of 12. That would be Magnesium or Mg.</span>
bagirrra123 [75]3 years ago
3 0

<em>Element X is an element of Mg which is located in group 2A and period 3</em>

<em>with 12 = atomic number and 25 = mass number</em>

\boxed{\boxed{\bold{Further~explanation}}}

The Atomic Number (Z) indicates the number of protons in an atom of an element. If the atom is neutral then the number of protons will be equal to the number of electrons. So the atomic number can also indicate the number of electrons.

So atomic number = number of protons = number of electrons

Mass Number (A) is the sum of protons and neutrons

Mass Number (A) = Number of protons + Number of Neutrons

So that the relationship between atomic numbers and mass numbers can be formulated as follows:

Atomic Number (Z) = Mass Number (A) - Number of Neutrons

In the following element notation,

\large{{{A}\atop{Z}}\right X}

Information

X = symbol of elemental atom

A = mass number

  = number of protons + number of neutrons

Z = atomic number

  = number of protons = number of electrons, on neutral elements

In an atom, there are levels of energy in the skin and sub skin.

This energy level is expressed in the form of electron configurations.

Charging electrons in the sub skin uses the following sequence:

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.

The location of the element group in the periodic system is determined by the number of valence electrons that fill the last sub-skin

The element period is determined from the valence shell (the largest main quantum number (n))

The chemical element group is divided into two, namely:

Group A, occupies sub skins s and p

Group B, occupies sub skin d

In the most probable question, the notation is meant

\large{{{25}\atop{12}}\right X}

So that shows:

12 = atomic number

25 = mass number

To determine the X element, we must know where the element is in the modern periodic system

Determining the location of the group and its period is sought by writing down the electron configuration

Because atomic number = 12, the number of electrons is also = 12, so the electron configuration is:

1s² 2s² sp⁶ 3s²

The last valence electron is in the 3s² orbitals so that:

Period: main quantum number (n) = 3

Group: because it ends at s orbitals with 2 electrons, the group is 2A (electrons occupying s and p orbitals are group A)

So element X is located in period 3 and group 3A. Elements that fulfill these 2 conditions are: Mg

\boxed{\boxed{\bold{Learn~more}}}

the electron configuration for barium (Ba) in noble-gas notation brainly.com/question/11147367

the formation of a bond.

brainly.com/question/11311275

quantum number

brainly.com/question/2292596

Keywords: the electron configuration, orbitals, period, group ,  the modern periodic system

You might be interested in
Consider 10.0 g of helium gas (He) in a rigid steel container. If you add 10.0 g of neon gas (Ne) to this container, which of th
Norma-Jean [14]

Answer: (e) The pressure in the container increases but does not double.

Explanation:

To solve this, we need to first remember our gas law, Boyle's law states that the pressure and volume of a gas have an inverse relationship. That is, If volume increases, then pressure decreases and vice versa, when temperature is held constant. Therefore, increasing the volume in this case does not double the pressure owning to out gas law, but an increase in pressure would be noticed if temperature is constant

6 0
3 years ago
51. The radius of gold is 144 pm and the density is 19.32 g/cm3. Does elemental gold have a face-centered cubic structure or a b
Serjik [45]

Answer:

Elemental gold to have a Face-centered cubic structure.

Explanation:

From the information given:

Radius of gold = 144 pm

Its density = 19.32 g/cm³

Assuming the structure is a face-centered cubic structure, we can determine the density of the crystal by using the following:

a = \sqrt{8} r

a = \sqrt{8} \times 144 pm

a = 407 pm

In a unit cell, Volume (V) = a³

V = (407 pm)³

V = 6.74 × 10⁷ pm³

V = 6.74 × 10⁻²³ cm³

Recall that:

Net no. of an atom in an FCC unit cell = 4

Thus;

density = \dfrac{mass}{volume}

density = \dfrac{ 4 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{6.74 \times 10^{-23} \ cm^3}

density d = 19.41 g/cm³

Similarly; For a  body-centered cubic structure

r = \dfrac{\sqrt{3}}{4}a

where;

r = 144

144 = \dfrac{\sqrt{3}}{4}a

a = \dfrac{144 \times 4}{\sqrt{3}}

a = 332.56 pm

In a unit cell, Volume V = a³

V = (332.56 pm)³

V = 3.68 × 10⁷ pm³

V  3.68 × 10⁻²³   cm³

Recall that:

Net no. of atoms in BCC cell = 2

∴

density = \dfrac{mass}{volume}

density = \dfrac{ 2 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{3.68 \times 10^{-23} \ cm^3}

density =17.78 g/cm³

From the two calculate densities, we will realize that the density in the face-centered cubic structure is closer to the given density.

This makes the elemental gold to have a Face-centered cubic structure.

3 0
3 years ago
The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the molecular formula of styrene?
Natalija [7]
You got the answer correct. If you would double check
given:C (12 g/mol) H (1 g/mol). 

12(8) + 1(8) = 104 g/mol

and for C2H4
12(2)+1(4) = 28g/mol

Also, chemical formula of styrene is<span> C6H5CH=CH2.</span>
7 0
2 years ago
Read 2 more answers
Equation 3x-5=-2x+ 10?<br> O<br> 0<br> x= 5<br> -5 = x<br> -15 = -5x<br> -5x = 15
Harman [31]

Answer:

are those the answer choice

7 0
3 years ago
PLS HELP
serious [3.7K]

4. True

5. The amplitude of the ripples decreases as the circumference of the circle increases.

<h3>What is a wave?</h3>

A wave is a disturbance that moves energy from one place to another.

Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation. Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each travelling in a wave-like pattern at the speed of light. Hence, the statement is true.

As the disturbance moves outwards the energy it carries is spread over a larger and larger region called the wavefront. For example, the ripples in the water lie in a circle with an ever-increasing circumference. The amplitude of the ripples decreases as the circumference of the circle increases.

Learn more about the Electromagnetic wave here:

brainly.com/question/3101711

#SPJ1

6 0
1 year ago
Other questions:
  • What is cellular respiration?
    11·1 answer
  • One atom of silicon can properly combined in a compound with
    5·1 answer
  • What is the color would phenolphthalein be if placed in water
    10·1 answer
  • 2nh3(l) → nh4+(am) + nh2−(am) where (am) represents solvation by ammonia. at the boiling point (−33°c), kam = 5.1 × 10−27. calcu
    14·1 answer
  • The density of quartz mineral was determined by adding a weighed piece to a graduated cylinder containing 50.3 mL water. After t
    13·2 answers
  • Avoiding an accident when driving can depend on reaction time. That time, measured in seconds from the moment the driver see dan
    14·1 answer
  • I need help with that question please help me I really need it so much I been struggling and stressing a lot please it is due to
    10·1 answer
  • What does the smoke in the tube prove scientifically?/
    5·1 answer
  • How much DNA can be extracted from an onion
    11·1 answer
  • 20,000 $ give a way but answer this first
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!