Starting with: Lithium atomic mass: 7 g/mol atomic number: 3 Use Lithium as a starting place for A, B, and C. What would happen

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Starting with: Lithium atomic mass: 7 g/mol atomic number: 3 Use Lithium as a starting place for A, B, and C. What would happen

if: A. A proton was added to Lithium (7) B. An electron was removed from Lithium (7) C. A neutron was added to Lithium (7) D. A proton, an electron, and 2 neutrons were removed from Lithium(7). Include the symbol, element name, atomic number and atomic mass in your answer for each.

Chemistry

1 answer:

Tems11 [2.7K] · Answer 1 · 2026-03-28T17:07:34+03:00

a. $_3^7Li$

b. $_{3}^{7}Li^+$

c. $_{3}^{8}Li$

d. $_{2}^{4}He^+$

Given lithium's atomic mass of 7 and atomic number of 3, we can express it in standard notation with the atomic mass as a superscript and the atomic number as a subscript:

$_3^7Li$

a. The atomic number signifies the total number of protons present in an element. Adding a proton to lithium will increase the atomic number by one. Additionally, modifying the atomic number alters the element, since each element has a distinct atomic number.

It's critical to acknowledge that the mass of an atom is the sum of protons and neutrons; thus, we would also add one to the mass number. This gives us some new species X with:

$_{3+1}^{7+1}X=_{4}^{8}X$

To identify X, we must locate an element with Z = 4 on the periodic table, which is beryllium:

$_{4}^{8}Be$

b. A standard lithium atom possesses an atomic number of 3, indicating it has 3 protons. Since it’s an atom, the positive charge from the protons equals the negative charge from the electrons. Thus, a neutral atom comprises the same number of protons and electrons.

Lithium begins with 3 electrons. If we remove one electron, it results in a lithium cation with a +1 charge, leading to a net charge of +3 from protons and -2 from electrons.

Hence, it can be represented as a lithium cation with a +1 charge:

$_{3}^{7}Li^+$

c. Neutrons, while neutral, contribute to the overall mass of an atom. Therefore, adding a neutron does not affect the overall charge (atomic number) of lithium.

However, this would augment the mass by 1, as each neutron (and proton) counts as 1 atomic mass unit. Since the atomic number remains unchanged, it would still be lithium.

$_{3}^{7+1}Li=_{3}^{8}Li$

d. By first removing a proton, the atomic number of Li decreases by 1 unit, as the atomic number aligns with the proton count:

$Z=3-1=2$

The mass will also reduce by 1 unit, accounting for the protons and neutrons:

$M=7-1=6$

Following this step, we end up with helium (which has an atomic number of 2) and a mass of 6:

$_{2}^{6}He$

Then, removing 2 neutrons will decrease the mass by 2 units while the charge of He remains unchanged, as this step does not involve protons and neutrons do not alter a nucleus's charge:

$_{2}^{6-2}He=_{2}^{4}He$

Lastly, if an electron is removed, this results in a helium cation with a +1 charge, leaving 2 protons and 1 remaining electron after removing 1 electron from helium which initially had 2 electrons in its atomic state.

$_{2}^{4}He^+$