Can someone please answer at least a few or something. I struggling out here since I’m dumb

3. Group

5. Valence electron

6. The atomic number tells you the presence of proton and electron.

Explanation:

The electrons which are present in the last shell or orbit is called valence electron and the shell is valance shell. When you go from left to the right side of the periodic table, number of shells remains the same but number of electron increases while when we go from top to bottom of periodic table, number of shell increases but the number of valance electrons remains the same.

the answer is alpha particles hope i you

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.