Fill in the blank. A pure substance has a/an composition.
A/An is composed of two or more types of matter that can be present in varying amounts.
A solution is a/an mixture.
A mixture that is not uniform throughout is a/an mixture.
A pure substance that cannot be broken down chemically is a/an .
A characteristic of matter that’s not associated with a change in its chemical composition is known as a/an property.
Wax melting is an example of a/an change in the state of matter.
A banana peel turning brown is an example of a/an change in the state of matter.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year

the electron configuration that you gave me has 16 electrons ergo it has 16 protons ergo it is the element sulfur.

here is table 2-2:

country

percent of eligible voters that voted

rank

united states

44.9%

138

canada

60.1%

107

costa rica

84.6%

14

hungary

66.9%

82

japan

57.0%

118

egypt

27.7%

159

south africa

85.5%

10

ans is no, the data set cannot be plotted as a single circle graph