What are elemental valencies What are the common elemental valences?

When the elements are combined with each other, the ratio of the number of reactant atoms is always constant. For example, one sodium must be bound to one chlorine. And one mg must be combined with two.

If it were not for this number ratio, the anions, cations, and the outermost electron shells of the atoms that make up the molecules of the covalent compounds would not be able to become stable structures. It is not possible to form stable compounds. And because the atom is the smallest particle that cannot be separated in a chemical reaction, when the elements are combined with each other to form a certain compound, the number of atoms of each element must be a certain simple integer ratio.

The concept of valency comes from this, then the number of atoms of an element that are mutually combined determines the valency of this element, and the valency is set to facilitate the representation of the number of atoms that are mutually combined. When learning valency, you should be aware of the rules for elemental valency in compounds.

In addition, it is stipulated that in elemental molecules, the valency of elements is zero, and the algebraic sum of positive and negative valencies of both ionic compounds and covalent compounds is zero.

Valency properties: When various elements are combined with each other, there is a fixed number of compounds between atoms, and valency is used to express this property.

Arranged according to atomic number.

The number of outermost electrons or - (8 - the number of outermost electrons).

Hydrogen leaker (qīng). Helium (hài). Lithium (lǐ). Beryllium (pí). Boron (péng).

2. Carbon (tàn). Nitrogen (dàn). oxygen (yǎng). Fluorine (fú). 氖 (nǎi).

3. Sodium (nà). Magnesium (měi). Aluminum (lǚ). Silicon (guī). Phosphorus (lín). Sulfur (liú).

4. Chlorine (lǜ). Argon (yà). potassium (jiǎ). Banquet rolling calcium (gài). Scandium (kàng). Titanium (tài). Vanadium (fán).

5. Chromium (gè). Manganese Huixiang potato (měng). Iron (tiě). Cobalt (gǔ). Nickel (niè). Copper (tóng). Zinc (xīn).

20 Common Chemistry Elements:

1 Hydrogen (qīng). 2 helium (hài). 3 lithium (lǐ).

4 Beryllium (pí). 5 boron (péng). 6 carbon (tàn).

7 nitrogen (dàn). 8 oxygen (yǎng). 9 fluorine (fú).

10 捖 (nǎi. 11 sodium (nà). 12 mg (měi).

13 aluminum (lǚ). 14 silicon (guī). 15 phosphorus (lín).

16 sulfur (liú). 17 chlorine (lǜ). 18 argon (yà).

19 potassium (jiǎ). 20 calcium (gài).

Calculating the valency of an element in a substance is as follows:

Valency indicates the number of electrons gained and lost by atoms when they are combined with each other.

Valency is also a property exhibited by an element in the formation of a compound.

When elements are combined with each other, the ratio of the number of reactant atoms is not fixed, but is determined by the number of electrons in the outermost shell of the atom. For example, a sodium ion (valency of +1, loss of an electron) must be combined with a chloride ion (valency of -1, gain an electron). And one magnesium ion (valency of +2, loss of two electrons) must be combined with two chloride ions.

If the algebraic sum of the valency of the ions of the formed compound is not zero, the anions and cations that make up the ionic compound and the outermost electron shell of the atoms that make up the molecule of the covalent compound cannot be made a stable structure. It is not possible to form stable compounds.

It is stipulated that in the elemental molecule, the valency of the element is zero, and the algebraic sum of the valency of the positive and negative ions composed of the positive and negative ions is zero, regardless of ionic compound or covalent compound. Ionic compounds, e.g., NaOH (sodium valency is positive 1 valence, hydroxide ion valency is negative 1 valence, and the compound is written as zero valent after canceling each other out).