Q1. This question is about the periodic table and argon.
(a) What order did scientists use to arrange elements in early periodic tables?
Tick () one box.
Atomic weight of element
Number of neutrons in an atom of
element
Size of atoms of element
Year element was discovered
Atomic weight of element?
Number of neutrons in an atom of element
Size of atoms in element
Year element was discovered

c, liquids evaporate, creating a gas

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.