True, Some Elements, are very abundant(common) on earth , and some are rare, the formula tells you how many atoms of each element are combined together, A substance is made of just one kind of atom is called element, False, Water is an element, the symbol of hydrogen is He.

لوحة الصدارة

النمط البصري

الخيارات

تبديل القالب

استعادة الحفظ التلقائي: ؟