Which characteristics of elements do you think are part of the organization of the periodic table?

You may
select more than one answer.

A. Quantity of the element on Earth

B. Size of the element

C. Order of discovery of the element

D. Structure of the element

E. Symbol of the element

F. Reactivity with other elements

G. Mass of a single atom of the element

A. Quantity of the element on Earth

C. Order of discovery of the element

E. Symbol of the element

G. Mass of a single atom of the element

Explanation:

A. Quantity of the element on Earth

The periodic table contains all the elements so far discovered by man.

C. Order of discovery of the element

The periodic table is distributed in such a way that they specify how many protons - a type of elemental particle-the atom contains.

E. Symbol of the element

It is attributed an atomic symbol to each of the elements that are part of the periodic table, for example for hydrogen H, for silver Ag, for helium He.

G. Mass of a single atom of the element

The mass number represents the number of protons and neutrons present in an atom. This number can also be seen in the periodic table

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2