Answer:
The answer to your question is below
Explanation:
Physical properties are the properties in which there is no change in the nature of the substance but there is a change in the physical state.
Chemical properties are the properties in which the substance changes its nature. A new substance is formed.
A. Ice melts in the sun. Physical p.
B. Copper is a shiny metal. Physical p.
C. Paper can burn. Chemical p.
D. A silver knife can tarnish. Physical p.
E. A magnet removes iron particles from a mixture. Physical p.
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Here is the link to a great video that explains your question nicely, hope this helps.
<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.
<span>In the Bohr model electrons in atoms can occupy allowed orbits where they do not emit energy. Exchange of energy with the surrounding environment occurs only when an electron "jumps" from an orbit to another. Hope this answers the question. Have a nice day.</span>
Answer:
The second answer choice
Explanation:
X seems to list attributes for opaque objects, and y lists attributes of Transparent objects.