Which element has 21 neutrons and 20 electrons?

Chemistry

2 answers:

mario62 [17]2 years ago

6 0

Scandium has 21 neutrons

LuckyWell [14K]2 years ago

4 0

Answer:

Calcium is your answer

Have a good day ahead

You might be interested in

How does flame spread over liquid depend on the flash point?

zvonat [6]

If the liquid is at or above its flash point, the flame spread rate is fast, and the entire pool is engulfed within seconds. ... As the liquid temperature decreases, flame radiation must both heat the liquid to the flash point temperature and supply the heat of vaporization.

6 0

3 years ago

Pls help mee with this

Whitepunk [10]

Answer:

C. Shield Volcano

Explanation:

Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior's shield.

4 0

2 years ago

An atom of 125Sn has a mass of 124.907785 amu. Calculate the binding energy in MeV per atom. Use the masses: mass of 1H atom = 1

Ksenya-84 [330]

Answer:

1.06×10³ MeV/atom

Explanation:

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

Also, atomic number of Sn = 5 0

Thus, the number of protons = 50

Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.

Mass number = Number of protons + Number of neutrons

125 = 50 + Number of neutrons

Number of neutrons = 75

Mass of neutron = 1.008665 amu

Mass of proton = 1.007825 amu

Calculated mass = Number of protons*Mass of proton + Number of neutrons*Mass of neutron

Thus,

Calculated mass = (50*1.007825 + 75*1.008665) amu = 126.041125 amu

Given mass = 124.907785 amu

<u>Mass defect = Δm = |126.041125 - 124.907785| amu = 1.13334 amu </u>

The conversion of amu to MeV is shown below as:-

1 amu = 931.5 MeV

<u>So, Energy = 1.13334*931.5 MeV/atom = 1.06×10³ MeV/atom</u>

3 0

3 years ago

Use Lewis diagrams to show how electrons are shared to form covalent bonds in compounds wit the following atoms. Write the formu

bixtya [17]

The Lewis structure/diagram for CH2O (aka Formaldehyde) can be written in either of the following ways shown in the picture.
The dots represent electrons in the valence shell of the atom (the outermost shell). The green dots are electrons that belong to the Oxygen atom, the blue belong to the Carbon atom, and the pink belong to the Hydrogen atoms.
Covalent bonds are bonds between atoms where atoms share electrons with each other. Atoms bond because they obey the octet rule ( the rule states that most atoms of main-group elements tend to want 8 electrons in their valence shells).
Oxygen has 6 valence electrons, Carbon has 4, and Hydrogen has 1. H does not follow the octet rule, but C and O do, so the atoms are arranged in this way so that the O and C atoms have a full octet of electrons in their valence.