Answer:
Explanation:
The unbalanced nuclear equation is
It is convenient to replace the question mark by an atomic symbol, , where x = the atomic number, y = the mass number, and Z = the symbol of the element .
Then your equation becomes
The main point to remember in balancing nuclear equations is that **the sums of the superscripts and the subscripts must be the same on each side of the equation**.
Then
84 = x + 2, so x = 84 - 2 = 82
210 = y + 4, so y = 206
Element 82 is lead, so the nuclear equation becomes
Answer:
2. Decreases
Explanation:
From the combined concept of entropy and the second law of thermodynamics, it can be concluded that during the positive change in entropy, the degree of randomness of a system increases.
But in case of photosynthesis, we see a negative entropy change because in the process of photosynthesis plants take disordered things as from the atmosphere and water from soil and finally make a highly ordered molecule Glucose, which is further used as a food product and source of energy by the plants. Thus it is clear that degree of randomness in decreasing in the process of photosynthesis and it is a negative change in entropy.
Answer:
Silver and gold do not react with dilute acids. The metals like Cu,Au,Ag are less reactive than hydrogen. They do not displace hydrogen from dilute acids. Those metals which are above in the reactivity series displace hydrogen from dilute acids.
Explanation:
Answer:
Explanation:
We can use the formula for momentum to calculate the mass.
Answer:
D. Ar.
Explanation:
The<em> </em><em>electron configuration</em><em> of the atom reflects how the electrons are distributed among the various atomic orbitals</em>. Just as for neutral atoms, we use the Pauli exclusion principle and Hund’s rule in writing the ground-state electron configurations of cations and anions.
<u>Ions formed from atoms of most representative elements have the noble-gas outer electron configuration of ns²np⁶.</u> In the formation of a cation from the atom of a representative element, one or more electrons are removed from the highest occupied n shell. The electron configuration of calcium and its ion is as follows:
Ca: [Ar]4s² Ca²⁺ : [Ar]