Answer:
C.) No. of electrons
Explanation:
A.) is incorrect. The atomic number represents the number of protons in an element. Nitrogen (N) and sodium (Na) always have a differing amount of protons.
B.) is incorrect. The mass number represents the number of protons and neutrons in an element. The number of neutrons and protons are specific to each element (disregarding isotopes). When elements ionize, these amounts are not altered.
C.) is correct. When an element becomes an ion, the number of electrons change. When nitrogen gains 3 electrons and sodium loses 1 electron, they end up having the same number of electrons (10).
D.) is incorrect. When elements ionize, the number of neutrons does not change. The only way two different elements could have the same number of neutrons is if at least one of the elements is an isotope. Isotopes are two or more atoms of the same element that differ in their amounts of neutrons.
Answer : The time passed in years is 
Explanation :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = X g
a - x = amount left after decay process = 
Now put all the given values in above equation, we get
Therefore, the time passed in years is
Answer:
a) ammonium ion
b) amide ion
Explanation:
The order of decreasing bond angles of the three nitrogen species; ammonium ion, ammonia and amide ion is NH4+ >NH3> NH2-. Next we need to rationalize this order of decreasing bond angles from the valence shell electron pair repulsion (VSEPR) theory perspective.
First we must realize that all three nitrogen species contain a central sp3 hybridized carbon atom. This means that a tetrahedral geometry is ideally expected. Recall that the presence of lone pairs distorts molecular structures from the expected geometry based on VSEPR theory.
The amide ion contains two lone pairs of electrons. Remember that the presence of lone pairs causes greater repulsion than bond pairs on the outermost shell of the central atom. Hence, the amide ion has the least H-N-H bond angle of about 105°.
The ammonia molecule contains one lone pair, the repulsion caused by one lone pair is definitely bless than that caused by two lone pairs of electrons hence the bond angle of the H-N-H bond in ammonia is 107°.
The ammonium ion contains four bond pairs and no lone pair of electrons on the outermost nitrogen atom. Hence we expect a perfect tetrahedron with bond angle of 109°.
Answer: Drugs.com is the site which have all we need regarding medicines and uses of medicines. It give the facility to search A-Z drugs, once you have searched the desired medicine by this feature of site, it further gives information about identification of pills, approval date, and interaction between drug-drug and drug- the food you eating, the manufacturing date of medicines. It doesn't give information about the calculators.
Therefore, (e) is the correct option here.
