Matter and Chemical Formula Let us learn about
Atoms and molecules
Element, compound and mixture
Chemical symbol and chemical formula
Atomicity and valency

Atoms are the basic units comprising matter, and interact in a variety of ways.

Explanation

The most fundamental unit of matter that makes up elements is called atoms. Atoms comprise nucleus-orbiting electrons- while protons and nuetrons make up a stable nuclues. Here, the neutrons are uncharged, while the negatively charged electrons are attracted to the positively charged protons at the atom's center

The number of protons the atom determines its atomic number, and the sum of protons and neutrons determine the atomic mass.

Elements in the periodic table, are typically represented by chemical symbols- abbreviations of their atomic name. They are arranged in order of valency- atoms in the same group typically have the same number f electrons on their valence shells, and thus their physical properties behave similarly (conductivity, melting points, boiling points).

Valence electrons, on outer valence shells, also influence bonding. The atoms donate, accept or share valence electrons in order to achieve more stable atoms. Bonding between elements form molecules, that may interact with molecules to form compounds.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!