Radioactive elements are the unstable nuclei of the atoms that release energy and radiation. The atomic number remains the same in case of the gamma radiation.
Gamma radiations are the particles that are released when the unstable atom undergoes decay and emits charged particles. These rays have no effect on the atomic mass and number of the atom.
These rays only emitenergy whereas alpha and beta decay produces energy and newparticle. An excited nucleus emits energy in the case of gamma decay that is unlike the other two decays.
Therefore, there is no change in the atomicnumber in gamma decay.
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Answer: It actually remains the same.
Explanation: Gamma radiation does not affect the atomic number or the atomic mass.
(2) Cl2(g) + 2NaF(aq)--> F2(g) + 2NaCl(aq)
(3) I2(s) + 2NaBr(aq)--> Br2(l) + 2NaI(aq)
(4) I2(s) + 2NaF(aq)--> F2(g) + 2NaI(aq)
The answer is: (1) Cl2(g) + 2NaBr(aq)-->Br2(l) + 2NaCl(aq).
In this chemical reaction chlorine change oxidation number from 0 to -1 (reduction) and bromine change oxidation number from -1 to 0 (oxidation).
Chlorine is stronger oxidation reagent than bromine.
In VIIA or group 17 (halogen elements) there are six elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and tennessin(Ts).
They have high electronegativity because they have seven valence electrons in their outermost energy level, so they can gain an electron to have the octet rule.
Going down in the group, element are weaker oxidazing reagent and less reactive.
Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
(2) oxalate (4) peroxide
B. Carbon dioxide
C. Water
D. Sodium hydroxide
Answer: D. Sodium hydroxide
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Neutralization reaction is a type of double displacement reaction where an acid reacts with base to produce salt and water.
Thus on reacting hydrochloric acid and sodium carbonate we get sodium chloride, water and carbon dioxide as products.
is less than
is equal to
has no relationship to
Answer: is equal to
Explanation: According to the law of conservation of mass, mass can neither be created nor be destroyed. The mass has to be same on both sides of the reaction and to make this happen, the number of atoms of every element must be equal in reactants and products.
2 moles of hydrogen weigh=
1 mole of oxygen weigh = 32 g
Mass of reactants = 36 g
2 moles of water weigh=
Mass of products = 36 g
Thus mass of reactants = mass of products = 36 g
b. liquids.
c. malleable.
d. gases.
Answer : At room temperature, none of the metals are gases.
Explanation :
The properties of metals are :
Generally all the metals are solid at room temperature but with exception, the mercury is liquid at room temperature.
Generally all the metals are hard but with the exception, sodium and potassium are soft and easily cut with the knife.
The metals are malleable, ductile, lustrous in nature.
Metals are good conductor or heat and electricity.
Hence, At room temperature, none of the metals are gases.
Answer: Option (d) is the correct answer.
Explanation:
It is known that most of the metals are solid at room temperature but with a few exceptions like mercury is a liquid at room temperature and sodium is a soft metal as it can be cut with a knife.
Also, metals are malleable in nature that is, they can be shaped into thin sheets.
But metals are never gases. Hence, we can conclude that at room temperature, none of the metals are gases.