An atom has 9 electrons and 9 protons at the start. if it loses 2 electrons, the net charge on the atom will be . if the atom instead gains 4 electrons, the net charge will be

If the atom loses 2 electrons, the net charge on the atom will be 2+

If the atom gains 4 electrons, the net charge on the atom will be 4-

Explanation:

An atom is smallest unit of a matter or substance.It consist of three subatomic particles : electrons, protons, neutrons.

Protons are positively charged, neutrons are neutral and both are located in nucleus where mass of an atom is concentrated.

Electrons are negatively charged and are located outside the nucleus where they orbit in different energy levels around the nucleus.

In an atom, when electrons are lost, the atom gains a positive charge and forms cation. In an atom, when electrons are gained, the atom occupies a negative charge and forms anion.

Thus an atom with 9 electrons and 9 protons will be electrically neutral.

On losing 2 electrons, there will be 7 electrons and 9 protons will have 2+ charge.On gaining 4 electrons, there will be 13 electrons and 9 protons will have 4- charge.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.