The force of gravity is approximately GmM/r^2. They will probably have a different value for gravity on their planet (as opposed to our 9.81 Newtons) due to differences in mass and radius, and so will have evolved differently (stronger/weaker muscles+bones). This is just a value substitution, not a fundamental shift in science. The maths of projectile motion still hold, and a right angled triangle still has sides proportional to 3,4,5. If you throw a spear on the moon it will travel farther, but the fundamental mathematics (which we know) is still exactly the same. The point of science is to find the universal relationships. No scientist gets excited over the fact that the acceleration due to gravity on earth is 9.81m/s^2, but it sure as hell is great to know that we can figure out the gravitational force due to any mass, anywhere in the universe, using only simple maths derived from proportionality. Those alien scientists will undoubtedly have a different answer for their planet, and they'll write the formula differently, but they'll definitely have an equivalent formula.
Different elements are determined by the number of protons. Things with 1 proton last for ages. Things with lots of nucleons (protons and neutrons) (like Uranium and all those Uuu elements on the bottom row of the periodic table) decay into things with fewer protons (and neutrons) pretty well. The more nucleons, generally the faster they decay. Fusion (like in stars) joins things with small amount of protons (Hydrogen) into things with more protons (Carbon, Oxygen, etc). This is why there is hydrogen everywhere. It has nothing to do with the mass of the star 'collecting' different elements. There are no 'unknown' elements, there are only hypothetical ones that we haven't managed to make yet because they have so many protons that they take a lot of energy to fuse, and because once we make them they decay within microseconds. It is impossible for there to be a planet with vastly different elements, because they just don't last, they shake themselves to bits and form more common elements. This is why there is lots of Iron in the earth, it is a very stable element which radioactive material (any element with lots of neutrons) eventually decays into.
If all our science were just done by looking up tables instead of finding universal mathematical truths, then there might be some validity. Drawing 9.81 or a big H on the ground in front of them won't mean shit, but drawing a diagram showing an understanding of gravity's inverse squared proportion to distance, or drawing the most basic element in the universe, will certainly show them your race has some sentience. Whether or not they understand what you're on about depends on the differences in notation, which is why the chart uses a simple approach towards numbers, and introduces these hypothetical aliens to our base 10 number system first.