Praise be to Allah, and peace and blessings be upon the Messenger of Allah.
A disbeliever is legally addressed by the obligation to believe and by the rulings of Islamic law. Therefore, he will be held accountable on the Day of Judgment for his disbelief, for the obligations he abandoned, and for the sins he committed.
The Qur’an indicates this in what Allah تعالى says concerning the people of Hell:
“What has caused you to enter Saqar? They will say: We were not among those who prayed, nor did we feed the poor. And we used to engage in vain discussions with those who engaged in them, and we used to deny the Day of Recompense.” [Al-Muddaththir: 42–46]
They mentioned abandoning prayer, failing to feed the needy, and denying the Day of Recompense among the causes of their entering Hell. This indicates that they are held accountable for the branches of deeds in addition to their fundamental disbelief.
The disbeliever is also held accountable for Allah’s blessings that he used in ways other than obedience. Allah تعالى says:
“There is no blame upon those who believe and do righteous deeds for what they consumed.” [Al-Ma’idah: 93]
The believer benefits from permissible things while maintaining faith and piety. As for the disbeliever, he does not thereby gain religious entitlement, even though he may benefit from such things in this worldly life in accordance with Allah’s universal decree.
The reckoning of the disbeliever on the Day of Judgment differs from that of the believer. Allah may give the believer an easy reckoning, causing him to acknowledge his sins, then concealing them from others and forgiving him.
As for the disbeliever, he will be confronted with his sins and exposed before creation. Allah تعالى says:
“And the witnesses will say: These are the ones who lied against their Lord. Surely, the curse of Allah is upon the wrongdoers.” [Hud: 18]
In conclusion: The disbeliever will be held accountable for his disbelief, for the obligations he abandoned, and for the sins he committed. His reckoning on the Day of Judgment is not like the reckoning of the believer.
And Allah knows best.