Question

1. Moving from left to right across a row of the periodic table, which of the following values

increases by exactly one from element to element?
(1 point)
isotope number
atomic number
atomic mass unit
mass number
2. The atomic mass of an element is (1 point)
the sum of the protons and neutrons in one atom of the element.
twice the number of protons in one atom of the element.
a ratio based on the mass of a carbon-12 atom.
a weighted average of the masses of an element’s isotopes.
3. Which general statement does NOT apply to metals? (1 point)
Most metals are ductile.
Most metals are malleable.
Most metals are brittle.
Most metals are good conductors of electric current.
4. Group 7A of the periodic table contains the (1 point)
most reactive nonmetals.
most reactive metals.
least reactive nonmetals.
least reactive metals.
5. The unit for atomic mass is (1 point)
gram.
amu.
pound.
none of the above

Answer 1

all of those are right but #2 is a weighted average of the masses of an element's isotopes.

Answer 2

1. Atomic Number - the number of protons settle in the nucleus of an atom and it is uniquely classifies a chemical element.

2. The sum of the protons and neutrons in - The atomic mass of an atom of a given element is approximately equal to the number of neutrons + number of protons in that atom. Example: is for Sodium The number of protons is 11 and the number of neutrons is 12. Add the two, you get the atomic mass of 23.

3. Most metals are brittle. It is wrong since most metals are malleable.

4. Most reactive non-metals. Atoms of these elements effortlessly form compounds by allocating or getting one electron when responding with atoms of the other elements.

5. amu. It is defined as exactly 1/12 the mass of an atom of carbon-12