Atomic chemistry is determined by valence electrons why

Valence electrons are electrons that are used to form chemical bonds.

The valence electrons of the main group element atom are the outermost electrons. When there are less than 4 valence electrons (I, II, III main group), it is easy to lose the outermost electrons, and the 8 electrons (h is 0 electrons, Li, Be, and B are 2 electrons) in the lower layer are exposed to reach a stable structure, and the more electron layers, the lower the period, the more volatile electrons, and the stronger the metallicity.

When there are more than 4 valence electrons (V, VI, VII main group), it is easy to attract electrons to obtain electrons until the outermost shell satisfies 8 electrons to reach a stable structure, and the fewer the number of electron layers, the higher the period, the easier it is to obtain electrons, and the stronger the non-metallicity.

When the valence electrons are equal to 4 (iv main group), it is not easy to obtain electrons and not easy to lose electrons, such as c has 4 outermost electrons, which generally forms covalent bonds with other atoms (such as c, h, o and halogen elements, etc.), and shares electron pairs, so that c atoms themselves and other atoms that form covalent bonds with them meet the requirements of 8 electrons (h is 2 electrons) to achieve a stable structure.

When the valence electrons are equal to 8 (0 group of noble gases, HE has only one layer, which is 2 electrons), the outermost electrons have reached a stable structure, so it is not easy to obtain electrons and lose electrons for group 0 elements, and generally appear in the form of elemental (noble gases) and have stable chemical properties, and only under certain special conditions do they react to form compounds.

It is determined by the gain and loss of outer electrons, for example, metals are prone to lose the positive valence of the outermost electrons.

Atom most. The number of electrons in the outer shell is determined.

Atoms are uncharged, and electrons are negatively charged; There are protons and neutrons inside the nucleus, the protons are charged, the neutrons are not charged, the nucleus density is extremely high, and the electron mass is extremely light and generally negligible. The volume of an atom is determined by the number of outer electron layers, and the mass is determined by the number of neutrons and protons in the nucleus.

Proton + proton = nucleus.

Nucleus + electron = atom.

According to the quark model, quarks are fractionally charged, with each quark having a +2 3e or -1 3e charge (e is the proton charge unit).

A neutron consists of two lower quarks and one upper quark, and since the upper quark has a +2 3e charge and the lower quark has a -1 3e charge q=-1 3e*2+2 3e=0, the neutron is not charged.

A proton is composed of two upper quarks and one lower quark, and since the upper quark has a +2 3e charge, the lower quark has a -1 3e charge, and 2 3e*2-1 3e=e, the proton has a positive charge.

The relationship between the relative atomic mass, the number of protons, and the number of neutrons is the mystery of the composition of matter.

It is the atom's ( ) that determines the chemical properties of an element

a Number of outermost electrons.

b Number of electrons.

c Relative atomic mass.

d Number of protons.

Answer. The chemical properties of an element are determined by the number of outermost electrons of an atom, and when the outermost electrons of an atom are less than 4, it is easy to lose electrons. When there are more than 4 and less than 8, it is easy to obtain electrons When the outermost shell is 8 electrons, the chemical properties of the element are the most stable

Therefore, the properties of element A, especially the chemical properties, are very closely related to the number of electrons in the outermost shell of the atom, and when the outermost electrons of the atom are less than 4, it is easy to lose electrons; When there are more than 4 and less than 8, it is easy to obtain electrons When the outermost shell is 8 electrons, the chemical properties of the element are the most stable

Test point of this question: The role of electrons outside the nucleus in chemical reactions

Comments: The properties of elements are closely related to the number of electrons in the outermost shell, and the gain and loss of electrons outside the nucleus tends to determine the chemical properties of the elements

Atoms are the smallest particles that cannot be redivided in a chemical reaction.

A positive atom contains a dense nucleus and a number of electrons that are negatively charged around the nucleus. Whereas, the nucleus of a negative atom is negatively charged, and the surrounding electrons are positively charged. The nucleus of a positive atom is made up of positively charged protons and electrically neutral neutrons.

The antiproton in the nucleus of the negative atom becomes negatively charged, thus making the nucleus of the negative atom negatively charged.

When the number of protons is the same as the number of electrons, the atom is electrically neutral; Otherwise, it is a positively or negatively charged ion. Depending on the number of protons and neutrons, the type of atom is different: the number of protons determines which element the atom belongs to, while the number of neutrons determines which isotope the atom is of that element.

Atoms make up molecules, and the same kind of charges repel each other in the molecules that make up the substance, and different kinds of charges attract each other.