Question

hi friends help me
correct answer will be marked as brainliest

Answer 1

2) K and Cl cuz they have equal no of protons and electrons

7) NaO, AlCl3, Na2SO4

Answer 2

1. a)5  b)5   c)3   d)5   e)4

2. K, Cl because they are atoms not ions like others and they are not specified by their charge. So their charge is zero. They have equal no of electrons and protons in it. So it is electrically neutral.

3. a)Atomic unit of atomic mass unit is defined as 1/12th of mass of 1 atom of C-12. It is equal to mass of 1 proton($1.672*10^{-27} Kg$)

b) AMU is used because it is much easier to write 'n u' it rather than (n*$1.672*10^{-27} Kg$).It has also a defined value so we can convert it into SI units or any other unit anytime we wan't. It also makes calculation easier.

4. a) Atomicity is defined as total no. of atoms in a molecule or ion.

   b)$O_{2}-2\\S_{8}-8\\Ar_{1}-1\\CO_{2}-3\\Na-1\\Cl^{-}-1\\NaCl-2$

5.  Atom :- It contains only one nuclie.

                 It has properties of single element.

                 It is rarely found independent.

                 Eg. O,S,Cs,U etc.

     Molecule :- It contains 2 or more than 2 atoms or nuclie.

                        It may or may not have all the properties of constiuent atoms or element.

                        It can exist independently.

                        Eg. $H_{2}O,O_{2},CO_{2},C_{6}H_{12}O_{6}$ etc.

6.  a)$Al_{2}(SO)_{3}$

    b)$Ba(NO_{3})_{2}$

    c)$CaCO_{3}$

    d)$(NH_{4})_{2}SO_{4}$

    e)$NaNO_{3}$

    f)$(CaH_{6})^{5-}$

7.$Na_{2}O$, $AlCl_{3}$, $Na_{2}S$

8.Ions are charged atoms or group of atoms which get charged by gaining or losing $e^{-}$ eg. $H^{+},O^{2-},(SO_{4})^{2-}$ etc

Ionic compounds are those compounds which are formed of ions like $NaCl, AlCl_{3} etc.$

Molecular compounds are compounds which are formed by any 2 or more than 2 different atoms or ions like $H_{2}O,CO_{2},CH_{4}$ etc.

9. a) A chemical formula is a representation of a molecule or ion which describes its composition and its charge.

b)  Metals must be written first.

     More electronegative element should be written first

     Charge of molecule must be written as an exponent of it including square brackets.

    It should be written according to the structure of molecule.

10.$H_{2}O-18u\\HNO_{3}-63u\\CO_{2}-44u\\CH_{4}-16u\\CH_{3}OH-32u$

Hope it will help you. It took me 14 minutes to type and calculate with all those formulas.