The atomic radii and main valencies of several short period elements are shown in the table below

The valency of l and r is +2 valence, which should be group a of the periodic table, and according to the radius relationship, r is be and l is mg; The valency of q and t both has a valence of -2, which should be the element of group a of the periodic table, the most ** of q is +6 valence, which should be the element s, and t has no valence and should be the element o; The valency of M is +3 valence, which should be the group a element of the periodic table, and according to the atomic radius of M greater than q and less than L, it should be known that it should be the same period as L, and it is an Al element

A metallic mg al, then the more intense the reaction between mg and acid, then the reaction rate of elemental and dilute hydrochloric acid under the same conditions is l m, so a is wrong;

b r is be, and al is located diagonally on the periodic table, the properties are similar, the hydrate of al oxide is amphoteric hydroxide, then the hydrate corresponding to the oxide of be may be amphoteric, so b is correct;

c The electronegativity of oxygen is very strong, and there are hydrogen bonds in ice and liquid water, but there are no hydrogen bonds in gaseous water, so c is wrong; d．mg

There are 10 electrons outside the nucleus, s

There are 18 electrons outside the nucleus, and the number of electrons outside the nucleus is different, so d is wrong

Therefore, b

A, K, L, M, R, N belong to short-period elements and the valency is +1, +2, +3, +2, +1, according to the highest positive valency of the element = the family number of the main group elements, it is determined that the five elements belong to the Ia, IIA, IIIA, IIA, and Ia, a, n belong to the same main group, K and R belong to the same main group, according to the periodic law: the atomic radius of the same main group of elements gradually increases with the increase of atomic number, Therefore, if the number of periods of k is greater than the number of periods of n, and the number of periods of l is greater than r, it is determined that k and m belong to the third period, r and n belong to the second period, and the difference between the atomic radius of l and m is small, so it is also the same period, that is, k, l, and m are na, mg, and al of the third period respectively, and the atomic number increases sequentially.

B, L, R are short-period elements, the atomic number is less than 19, the valency of L and R is +2, according to the highest positive valency of the element = the family number of the main group elements, L and R belong to the IIA group, the atomic radius of L is greater than the atomic radius of R, and the atomic radius of the same main group gradually increases with the increase of atomic number, so L and R are mg, be, and rcl respectively

It's beclbecl

It is a covalent compound, and the outermost shell of the Be atom is two electrons, and two shared electron pairs are formed with the two Cl atoms, so that the outermost shell of Be is 4 electrons, so B is wrong;

C. According to the valency, the highest positive valency of the element = the family ordinal number of the main group elements, the lowest negative valence of the element = the family number of the main group elements -8, know that q and t are the first VIA group, and the atomic radius of Q is greater than the atomic radius of T, which are all short-period elements, Q is the S element, and the most ** oxide is SO

After dissolving in water, so

ho=hso

hso2hso

HSOs present in water

It is SO ionized, not SO

ionized, so the electrolyte is h

SO is not SO

Therefore c is wrong; d. According to the short-period element, the highest positive valency of the element = the family ordinal number of the main group elements, the lowest negative valence of the element = the family ordinal number of the main group elements -8, the atomic radius of the same main group gradually increases with the increase of the atomic number, so k and n belong to the first group ia, q and t belong to the group via, the atomic radius of k is greater than the atomic radius of n, and the atomic radius of q is greater than the atomic radius of t, so t is the o element, q is the s element, k is the na element, and na is in o

The product after combustion is NA

o It is easy to form ionic bonds between reactive metals and reactive non-metals, so Na and O

Ionic bonds are formed, and covalent bonds are easily formed between active non-metals, so O and O form non-polar covalent bonds, so d is correct

Therefore, choose D

c 6, the atomic radius and the main compound code dry prices of several short-period elements are shown in the following table:

Element code. xyz

MRQ atomic radius (10-10 m).

The main late front valence. Highest regular price.

Lowest negative price. The following statement is true.

A elements X and Q formed by the source of the compound can not contain covalent bonds b x, y, m elemental reaction with water respectively, y is the most violent, c x, z, r most ** oxide hydrate can react with each other in pairs, d y oxide hydrate acidity must be stronger than r oxide hydrate acidity.

Solution: The valence of x and y is +2 valence, which should be group a of the periodic table, and according to the radius relationship, y is be and x is mg;

The valency of z and t both has a valence of -2, which should be the element of group a of the periodic table, the most ** of z is +6 valence, which should be an element s, and t has no valence and should be an element o;

The valency of r is +3 valence, which should be the element of group A of Qinxiang in the periodic table, which can be known according to the radius greater than y and less than x, and the same period as x, which is an al element

The valency of x and y is +2 valence, which should be group a of the periodic table, and according to the radius relationship, y is be and x is mg;

The valency of z and t both has a valence of -2, which should be the element of group a of the periodic table, the most ** of z is +6 valence, which should be an element s, and t has no valence and should be an element o;

The valency of r is +3 valence, which should be the element of group a of the periodic table, which can be known according to the radius greater than y and less than x, and the same period as x, which is the al element

A The stronger the metallicity, the faster its reaction rate, so the speed of the reaction between elemental matter and dilute sulfuric acid is X r Y, so A is wrong;

b Oxygen ions and magnesium ions with the same electron shell structure, the larger the atomic number, the smaller the ionic radius, so the ionic radius: t2- x2+, so b is correct;

The stronger the metallicity of element c, the stronger the alkalinity of the hydrate of the most ** oxide, and the strongest metallicity of magnesium, so the alkalinity of magnesium hydroxide is the strongest, so c is wrong;

The stronger the non-metallic nature of the d element, the easier it is to dislike the combination of elemental and hydrogen gas, and the non-metallic nature of the oxygen element is greater than that of the sulfur element, so the combination of oxygen and hydrogen is easier than that of the sulfur element and the hydrogen element, so D is wrong;

Therefore, b 10 is selected, and the atomic radii and main valencies of several short-period elements are shown in the table

Element symbol x y z r t atomic radius (mm) Main valency +2 +2 -2, +4, +6 +3 -2 According to the information in the table, it is judged that the following statement of bond volt is correct ( ).

a The rate at which elemental matter reacts with dilute sulfuric acid: r y x

b Ionic radius: t 2- x 2+

The most ** oxide of element c corresponds to the alkalinity of the hydrate: y r x

d Ease of combining elemental matter with hydrogen: z t

A, K, L, M, R, N five elements belong to the short-period elements and the valency is +1, +2, +3, +2, +1 respectively, according to the highest positive valency of the element = the family number of the main group elements, the determiner let the source five elements belong to the Ia group, the IIA group, the IIIA group, the IIA group, the Ia group, the Ia group, a n, a n belong to the same main group, k and r belong to the same main group, according to the periodic law: the atomic radius of the same main group elements gradually increases with the increase of atomic number, Therefore, if the number of periods of k is greater than the number of periods of n, and the number of periods of l is greater than r, it is determined that k and m belong to the third period, r and n belong to the second period, and the difference between the atomic radius of l and m is small, so it is also the same period, that is, k, l, and m are na, mg, and al of the third period respectively, and the atomic number increases sequentially.

B, L, R are short-period elements, atomic number is less than 19, the valency of the first state L and R are +2, according to the highest positive valency of the element = the family number of the main group elements, L and R belong to the IIA group, the atomic radius of L is greater than the atomic radius of R, and the atomic radius of the same main group gradually increases with the increase of atomic number, so L and R are mg, be, and rCl respectively

It's beclbecl

It is a covalent compound, and the outermost shell of the Be atom is two electrons, and two shared electron pairs are formed with the two Cl atoms, so that the outermost shell of Be is 4 electrons, so B is wrong;

C. According to the valency, the highest positive valency of the element = the family ordinal number of the main group elements, the lowest negative valence of the element = the family number of the main group elements -8, know that q and t are the first VIA group, and the atomic radius of Q is greater than the atomic radius of T, which are all short-period elements, Q is the S element, and the most ** oxide is SO

After dissolving in water, so

ho=hso

hso2hso

HSOs present in water

It is SO ionized, not SO

ionized, so the electrolyte is h

SO is not SO

Therefore c is wrong; d. According to the short-period element, the highest positive valency of the element = the family number of the main group elements, the lowest negative valence of the element = the family number of the main group elements -8, the atomic radius of the same main group gradually increases with the increase of the atomic number, so k and n belong to the ia group, q and t belong to the VIA group, the atomic radius of k is greater than the atomic radius of n, and the atomic radius of q is greater than the atomic radius of t, so t is the o element slippery, q is the element s, k is the element na, and na is in o

The product after combustion is NA

o It is easy to form ionic bonds between reactive metals and reactive non-metals, so Na and O

Ionic bonds are formed, and covalent bonds are easily formed between active non-metals, so O and O form non-polar covalent bonds, so d is correct

Therefore, choose D

The valency of x and y is +2 valence, which should be group a of the periodic table, and according to the radius relationship, y is be and x is mg; The valency of z and t both have a valence of -2, which should be repented as the group a element of the periodic table, the most ** of x is +6 valence, x should be the s element, t has no positive valence, and t should be the o element; The valency of r is +3 valence, which should be the group a element of the periodic table, and the radius of the root fiber chain is greater than z and less than x, which should be the same period as x, and r is the al element

A. Metallic mg al, mg be, the stronger the metallicity, the more intense and faster the reaction with acid, so the rate of reaction between elemental and dilute sulfuric acid is mg al

mg be, i.e. x r, x y, so a is wrong;

b、al（oh）

Gel particles are a lot of al (ruined grandson oh).

aggregates, larger than solution ions; The electron shell arrangement is the same, and the larger the number of nuclear charges, the smaller the ionic radius, so the ionic radius O

Magal particle radius: Al(OH).

Colloidal pellet omgal

Therefore b is correct; C. Metallicity mg al, mg be, the stronger the metallicity, the stronger the alkalinity of the hydrate of the most ** oxide of the element, so x r, x y, so c is wrong;

d. Non-metallic O s, the stronger the non-metal, the easier it is to combine the elemental with hydrogen, so the difficulty of the combination of the elemental and hydrogen is O S, that is, Z t, so D is wrong

Therefore, b

A, K, L, M, R, N belong to short-period elements and the valency is +1, +2, +3, +2, +1, according to the highest positive valency of the element = the family number of the main group elements, it is determined that the five elements belong to the Ia, IIA, IIIA, IIA, and Ia, a, n belong to the same main group, K and R belong to the same main group, according to the periodic law: the atomic radius of the same main group of elements gradually increases with the increase of atomic number, Therefore, if the number of periods of k is greater than the number of periods of n, and the number of periods of l is greater than r, it is determined that k and m belong to the third period, r and n belong to the second period, and the difference between the atomic radius of l and m is small, so it is also the same period, that is, k, l, and m are na, mg, and al of the third period respectively, and the atomic number increases sequentially.

B, L, R are short-period elements, the atomic number is less than 19, the valency of L and R is +2, according to the highest positive valency of the element = the family number of the main group elements, L and R belong to the IIA group, the atomic radius of L is greater than the atomic radius of R, and the atomic radius of the same main group gradually increases with the increase of atomic number, so L and R are mg, be, and rcl respectively

2 is BECL

2，becl

2 is a covalent compound, the outermost shell of the Be atom is two electrons, and two shared electron pairs are formed with the two Cl atoms, so that the outermost shell of Be is 4 electrons, so B is wrong;

C. According to the valency, the highest positive valency of the element = the family ordinal number of the main group elements, the lowest negative valence of the element = the family number of the main group elements -8, know that q and t are the first VIA group, and the atomic radius of Q is greater than the atomic radius of T, which are all short-period elements, Q is the S element, and the most ** oxide is SO

3 After dissolving in water, SO3+H

2o=h2so

4，h2so

4=2h+so42-

H present in water

SO42- is H2SO4

Ionized, not so

3 ionized, so the electrolyte is H2SO

4 is not SO3, so C is wrong;

d. According to the short-period element, the highest positive valency of the element = the family ordinal number of the main group elements, the lowest negative valence of the element = the family ordinal number of the main group elements -8, the atomic radius of the same main group gradually increases with the increase of the atomic number, so k and n belong to the first group ia, q and t belong to the group via, the atomic radius of k is greater than the atomic radius of n, and the atomic radius of q is greater than the atomic radius of t, so t is the o element, q is the s element, k is the na element, and na is in o

The product after combustion in 2 is Na2O

2. It is easy to form ionic bonds between reactive metals and reactive non-metals, so Na+ and O

2- Ionic bonds are formed, and covalent bonds are easily formed between active non-metals, so O and O form non-polar covalent bonds, so D is correct

Therefore, choose D