The observed mass of the sun is 6.270 * 10 ^ 26 g but the actual mass of sun is 5.97*10^ 24 kg . The percent error in measurement is 4,78 %

Icant see the pictures 

Its strengthits conductivity of heat and electricity its shiny colourmalleable and ductility

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.